
Stupidity: How on earth did those helicopter gunship pilots survive a tour of duty in Vietnam? They are too stupid to tie their own shoelaces. They have encountered a thirty metre tall ape which is intent on killing the lot of them by grabbing their helicopters and smashing them to the ground, so they have two clear choices - a) use their heavy, mounted machine guns or the grenade launchers fitted to the assault rifles carried by the troops on board to shoot the thirty metre tall ape to ribbons from a couple of hundred metres away, well out of its reach or b) fly straight up to it and present an easy target, allowing it to kill the lot of them by grabbing their helicopters and smashing them to the ground. Every single one of them ticks box b). Idiots.

Stupidity: After Josh runs away from home after being turned into an adult, nothing seems to be done about his "disappearance." The only indication that he is missing is his picture on the back of a milk carton. There's no flyers about him missing. No mention of his disappearance in any newspapers or TV news about his mom saying that he's been "abducted" by a stranger. Even when Josh writes a letter home, he uses the actual address of where he's staying, but no cops turn up at his door after his mom receives the letter.

Stupidity: The Death Star comes equipped with a powerful tractor beam capable of capturing a ship the size and agility of the Millennium Falcon. Why don't they use it against the rebel fighters attacking them at the end of the film? Okay, Obi-Wan Kenobi turned it off earlier but I find it hard to believe that someone who has never before visited the largest, most complex space station in the Universe and who was previously unaware of its very existence can disable a fundamental security system but the people who designed, built and run the whole thing can't work out how to switch it back on. They should have no problems with this, considering the fact that Obi-Wan didn't damage it.
Suggested correction: Obi Wan disrupted the battle at a critical time causing much confusion. We could chalk this oversight up to "Fog of War" - that in the heat of battle it's normal for commanders to overlook obvious things and seem to act stupidly. It would also be reasonable to assume that the fighters were too close for the tractor beam emitter to target them.
This scenario would require every single person on the Death Star who was involved in the maintenance of vital defence systems not noticing that one of them had been switched off! Not ONE person noticed? Obi Wan did not disable the tractor beam during "the heat of battle." There was a considerable time lapse between his switching off the tractor beam and the climactic final battle, during which time it would have been switched back on. When the Millenium Falcon leavs the Death Star Han Solo remarks that he hopes that "old man" succeeded in disabling the tractor beam, implying that those on the Death Star would be trying to use it. Even then, they didn't notice it had been switched off? Not sabotaged, not disabled, switched off.
Good point. This was definitely stupidity on the part of the Death Star crew, but not stupid as a plot point. It does happen in combat regularly. In 1987 the USS Stark was hit by 2 Iraqi Exocet missiles after challenging a single fighter. The ships' Close-in Weapons System should have easily shot the missiles down, but the investigation showed that no-one had noticed that the system had not been turned on.
They didn't use the tractor beam when the gang was escaping in the Falcon because they WANTED them to get away. The Empire placed a tracking beacon onboard so as to be able to find the hidden Rebel Base. As to how the Falcon was snagged originally: yes, they had just exited hyperspace, but they were not relatively fast; they were preoccupied with the TIE fighter (incapable of light speed) and the small moon right up to the point they were trapped in the tractor beam (and realizing "that's no moon!"
Suggested correction: The Falcon was travelling towards the Death Star when it was caught in the tractor beam. The tractor beam was properly turned back on by the time it travelled to Yavin. The rebel fighters are too small and quick to be held in a tractor beam and there are so many of them so it would be near impossible to trap enough to make a difference.
As I have already pointed out, assigning technical limitations to a wholly fictional piece of technology is absurd. As to "flying towards the Death Star" - the X and Y wing fighters are shown doing just that. As for being too quick, the Millenium Falcon is decelerating from superluminal speeds when it is captured in the tractor beam. That's pretty bloody fast in anyone's books.
The key phrase here is "fictional piece of technology", there is no way to understand how it works. Any explanations is pure conjecture.
It's flat out stated by General Dodonna in the battle briefing that the Death Star's defenses are based around repelling attacks by capital ships, not fighters. The targeting may not be exact enough.
Actually, claiming a fictional piece of equipment can't behave the way you think it should is somewhat silly. The previous explanation that the tractor beam's limitations were the reason for not using it during the battle makes perfect sense.

Stupidity: Steve Trevor is the leader of a group of Allied spies, and they are traveling with a gorgeous woman who has shown to have amazing fighting skills and super powers, but they allow a group photo to be taken with Diana in her armor. They don't know who is taking the photograph nor what they intend to do with it. Their photograph circulating through a news publication or passed on to an enemy's intelligence service could compromise himself and the rest of his team, and they would absolutely know that. Undercover agents do not pose for photographs.
Suggested correction: The photographer is not a reporter, he is one of the villagers. The photo was not taken to be circulated through print media, it was taken by the villagers to commemorate the day they were liberated. There only appears to be one copy of the photograph (which Bruce Wayne finds and sends to Diana), so the likelihood of it falling into the German's hands is incredibly slim.
It does not matter who took the photograph or why, or what he chooses to do with it. Undercover agents do not pose for photographs.

Stupidity: When Johnny is captured by Roarke and his followers, Danny gives him the power of the Ghost Rider back. Roarke knows what Danny is doing, but doesn't order his men to stop him, or even attempt to stop Danny himself.

Stupidity: When Anna, Velkan and the villagers successfully trap the gray werewolf in a huge cage, the villagers start firing on it. Anna says they need to use Velkan's gun because it has silver bullets in it. Since everybody knew they were fighting a werewolf, all of them should have had silver bullets for their guns.

Stupidity: The Engineer and Fireman of the Polar Express train crew should have known better than to not bend back the the metallic prongs of the cotter pin, which would have prevented the cotter pin from coming loose and causing all those problems in the driving of the train.
Suggested correction: As you yourself stated, the whole thing is likely a dream, where "normal" reality doesn't apply. In the "real world", the train would never be able to do any of the things that it does in the film.
Dream or not, it is still a stupidity of the train crew to not secure a pin that could work itself free of the controls of the locomotive.
Dreams are often unrealistic. There is no mistake.
The entry doesn't say anything about the entire trip to the North Pole being a dream.

Stupidity: It's stated that Imhotep will fear cats until he has fully regenerated and two different scenes show him fleeing in terror at the sight of a cat. Despite this, none of the characters that Imhotep is trying to kill that are fully aware of his weakness even think to have a cat with them at all times.

Stupidity: The commando mission to save Chewbacca starts gunning down a few Stormtroopers in the hangar. The heroes then go on leaving the troopers lying down on the floor in front of the ship, in plain view. They don't hide them nor ask the droids (who have enough strength and tools to pull them in) to, in fact they tell them to stay put. No wonder they are found out later (after a ridiculously long amount of time).
Suggested correction: Hiding the bodies would have been a waste of time, anyone who came to the hangar would immediately notice that the guards stationed there were missing and there was now a strange ship parked there.
The droids have all the time in the world, and people just passing by are "more immediately" bound to notice corpses in the middle of a hangar rather than possibly maybe question the fact that you don't see guards in that part of the hangar or investigate the ship - which could approach without anyone taking exception by appearance alone. At least remove the bodies directly in front of the damn ship!
Why would they be more likely to notice dead guards than no guards?
Anyone passing by might well thing the patrols were just out of sync, or a shift change. Sure they might investigate further, but they might not bother. Whereas a couple of dead bodies? Immediate red alert. Worth taking 30 seconds to hide them, surely.
Perhaps, but then it's made irrelevant 1 minute later as Finn and Poe run down a hallway blasting about a dozen stormtroopers.
For that matter, 1 SECOND later they kill stormtroopers in the far part of the hangar. They are killing people all over the ship during their mission and it's not like they hide every single one of them, but they leave two bodies *exactly* in front of their ship (and telling the droids to stay put). You can even see later that there is a stormtrooper with his weapon pointed exactly where those two corpses are, with the 'smart' commanding officer asking "whose ship is this?" at the sight of that. Maybe I am spoiled by a trope here, but it's the first time that I see someone in an action movie leaving corpses right in front of their only escape route/vehicle, that's so counterintuitive. (Did they even have an escape plan, actually? I don't like hypotheticals, but gee, if only she did the Jedi mind trick thing to those 2 guards who came over to inspect the ship instead of doing it later. But I digress).

Stupidity: Once the casket was left in the mercury in the tomb, the ropes and pulleys should have been taken away instead of left in place for it to be retrieved. For something so evil why would any sane person want to bring it back out?

Stupidity: When Colonel Hardy is about to crash the ship he's flying into a building, Faora sees it and she has more then enough time to leave the ship and get to safety, but she does nothing and just stands there.

Stupidity: During one of the test drives, the hook that Hiccup uses to fasten himself to Toothless gets bent, so he takes Toothless to the blacksmith to cut the line. There are two ways he could have easily avoided this: He could just unhook the saddle, take that to the blacksmith and cut himself loose, or he could just untie the leather strap. What he does here is needlessly risky and just there for his awkward conversation with Astrid.

Stupidity: When Spider-Man confronts Aleksei Sytsevich in the truck while he's plowing through the busy streets of New York, he sits there and starts cracking jokes instead of immediately trying to stop the truck, effectively allowing Sytsevich to potentially injure or kill numerous people in the process, as well as to wreck many vehicles. He even allows Sytsevich to fire a gun out of his window and into the open crowd instead of trying to disarm him as soon as he sees the gun.

Stupidity: After the Slick devours Laverne, Randy jumps into the water and swims for shore with the Slick following. Even though Randy made it to shore, he stops and turns to confront the Slick, screaming that he beat it. When Randy turns around, the Slick immediately envelopes him. If Randy had just got up and started running instead of facing the Slick, he would have lived.
Suggested correction: This is a deliberate movie making technique to make the audience think the character has escaped but at the last second a surprise is thrown in. It's the same as hanging over the body of the killer. It doesn't come under stupidity.
Yes, it does. In any movie where someone comes face to face with either a supernatural enemy or even a regular one, confronting it is extremely stupid because the character could have simply walked away and made it to safety. The character confronting the killer is stupid because they'll always be killed. Better to do the smart thing and run as far and as fast as possible.
A example of a valid stupidity entry is an astronaut taking his helmet off when in space because he's an expert and knows better. A stupid person doing something stupid is considered a stupidity entry (which is essentially a plot hole writers use to move the story in a particular direction it wouldn't have gone otherwise). A character making the wrong choice because they underestimate the situation isn't a minor plot hole, in real life people underestimate opponents all the time, and movies exploit that all the time in their plot development (i.e. Apollo underestimating Rocky).
Suggested correction: Randy's decision isn't what constitutes a "stupidity" mistake. Stupidity mistakes are minor plot holes, which means characters can act stupid. Plus, when Randy gets to shore he's worn out so he tries to catch his breath. He then says he's won because he under estimated the Slick's ability to get him (which would fall under the category of "celebrating too early").
Put yourself in Randy's place. If you're friends were eaten by a huge slick like monster and you were swimming to shore with it chasing you, after making it safely to shore, would you want to turn around to confront it. No. That would be stupid because confronting it will certainly get you killed the moment your back is turned. The smart thing to do would be to keep running. Randy facing it was very stupid. Had he done the smart thing and kept going after he made it to shore, he would have survived. Stupidity killed him. Pure and simple.
First off, you said it would certainly kill you once your back is turned, which means if you're running away, your back is turned and if you confront it, your back isn't turned. But, he never tried to confront it. He just celebrates beating it. However, Randy thought he was safe once on land because he thought the creature couldn't attack him or reach him, so in Randy's mind he wasn't doing anything stupid. He thought he was safe, he thought he won. He was tired and sat to rest. But that's part of his character and his character traits. But, acting stupid isn't a "stupidity" mistake. Otherwise movies like "Dumb and Dumber" would just be thousands of stupidity mistakes because stupid characters are acting stupid. Now, if Randy knew the creature could kill him in water and he turns to celebrate his victory, or stops to rest, in the water, that could be a "stupidity" mistake since his character was already shown to know he can't stop in the water and the writers ignored what was already established as his character. Stupidity mistakes just are minor plot holes that go against already establish character traits or established facts/statements in the film.
Not only that, but, Randy was acting stupid since he chose to face it rather then run.
If you re choosing to say its a stupidity because they choose to fight rather than run then that's a moot point because you wouldn't have a movie in the first place! Movies get a degree of latitude when it comes to reality (people can be shot 7 times and still walk away as the credits roll) so rather than stupidity, this is under slightly suspended reality of how an actual person would behave. In this segment, we're talking about an oil slick with a mind of its own. 100% reality has to take a back seat where plot forwarding is concerned.

Stupidity: Why does the team choose to enter the shimmer from Area X and then trek for miles to the lighthouse? They could travel by sea and stage an amphibious landing on the shore right at the foot of the lighthouse. Obviously this would make for a very short movie, but this choice still needs to be explained in the plot.
Suggested correction: I thought it was an obvious tactical choice to go by land. If the mysterious shimmer radiates in all directions for miles, as it seems to in the movie, then it would also radiate for miles out to sea. A recon team is going to have a lot more options to deal with any "weirdness" on the ground rather than on a boat or in the water. (Also, the book "Annihilation" on which the movie is based makes it clear that there are some really big, nasty things swimming around in the water!).

Stupidity: When Han tells Drydon Vos that he and Tobias will steal unrefined coaxium from the mines on Kessel, Vos initially says no, as Crimson Dawn's relationship with the Empire would be at risk. Han then explains that the Empire wouldn't know they were working for Crimson Dawn. Vos then agrees but insists his top lieutenant Qi'ra accompany them, even though she is a known associate of Crimson Dawn and literally has their symbol branded on her wrist.