Trivia: Whenever there is an accident involving the general population you can ALWAYS hear amongst the groans a man saying, "My leg..."Some examples are: 1. In the episode "Hall Monitor" when SpongeBob directs all the cars in the wrong direction, you can see a bunch of wrecked cars, and then you hear the recording "My leg..." 2. And in "Boating School" when SpongeBob crashes into the lighthouse you can hear a man moan "My leg..." 3. On "The Chaperone" episode, when all the kids at the prom get hurt during "The Sponge" song you can hear "My leg..." 4. This is the one in "Culture Shock" where Squidward puts on a talent show.When Pearl puts on her performance, and jumps up and down, people start crashing through the air.At this part the "My leg..." sound is heard 5. On "Sleepy Time, when SpongeBob is in Plankton's dream, Plankton says "Peek-a-boo I see you, Zap!", and you hear "My leg..." 6. In the episode "Aarrgh!", a fish walks in the Krusty Krab and says "Whip up those patties Crabs." and something else, and Mr.Krabs throws him out and he says "My leg..." 7. In "Walking Small", when SpongeBob gets out his towel, he fans all the sound out of it.All the fish leave instantly.You can hear the recording "My leg..." 8. On "Karate Choppers", when SpongeBob knocks a guy out thinking he's Sandy he says "My leg..." 9. And in "Something Smells" when SpongeBob makes the marching band fall over and fly everywhere you can, once again hear "My leg..." Also, in the movie, a joke was made on this, where instead he says "My eyes!"
Nature Pants / Opposite Day - S1-E9
Trivia: When Spongebob runs off to live with the Jellyfish, Sandy says, "I'll give him a week." Squidward says,"I'll give him 11 minutes." 11 minutes is the length of this episode.
Trivia: Spongebob's first words as a baby were, "May I take your order?"
Club SpongeBob / My Pretty Seahorse - S3-E12
Trivia: Similar to what Squidward did in "Nature Pants," in "Club Spongebob" he says "Why must every 11 minutes of my life..." 11 minutes is the average length of a Spongebob episode.
Trivia: In "Missing Identity," the waitress says "Well, you managed to kill 11 minutes." This is an inside joke because the average length of a Spongebob episode is 11 minutes.
Sandy's Rocket / Squeaky Boots - S1-E8
Trivia: "Squeaky Boots" is based on "The Tell-Tale Heart" by Edgar Allan Poe.
Trivia: In "Where's Gary?" when Spongebob takes the Dirty Bubble Challenge, look closely at the paddleball box; it has the Nickelodeon logo on it.
Trivia: In the episode "Karate" when Sandy is about to pour the hot sauce over Spongebob's tongue, the face on the sauce that laughs and taunts Spongebob is Tom Kenny, the voice of Spongebob.
Trivia: In the "When Worlds Collide" song the caveman is played by Bill Fagerbakke, the voice of Patrick.
Trivia: Plankton's wife, Karen, is named after Steve Hillenburg's wife. Plus, the actor is Jill Talley, the wife of Tom Kenney.
Trivia: In the episode "Spongebob Meets The Strangler", the Tattle Tale Strangler is based on a killer from the movie "Cry Baby Killer".
Krab Borg / Rock-a-Bye Bivalve - S3-E8
Trivia: In "Krab-Borg" when Spongebob says who could be a robot, he says, "What if Mom is a robot?" and "What if Uncle Sherm is a robot?" Sherm is the name of one of the writers of Spongebob Squarepants, Sherm Cohan.
Sailor Mouth / Artist Unknown - S2-E15
Trivia: In Sailor Mouth, Squidward's line, "Don't you mean there are only seven?" is a reference to George Carlin's "Seven Words You Can't Say On TV".
Trivia: Stephen Hillenburg, the show's creator, provided the lips for Painty the Pirate (the pirate who sings the theme song). He also does Potty the Parrot's voice.
Trivia: In the Karate Island episode, the voice of the leader is Pat Morita, star of The Karate Kid.
Mermaidman Begins/Plankton's Good Eye - S8-E22
Trivia: The Mermaid Man and Barnacle Boy Origin Special states that Mermaid Man and Barnacle Boy's names before they became underwater heroes were Ernie and Tim. Ernie and Tim are the names of the people who voice Mermaid Man and Barnacle Boy.
Trivia: The guy taking a shower in "Neptune's Spatula" and "Suds" is Tom Kenny, the voice of SpongeBob.
Mermaid Man and Barnacle Boy III / Squirrel Jokes - S2-E4
Trivia: Patrick says "I'm thinking in a number between 1 and 100, what is it?". Man-ray says "62". However, in Spanish, he says "72".
The Patty Caper/Plankton's Regular - S6-E8
Trivia: When Patrick, as the "sketch artist", draws Squidward, Squidward is lying on the ground eating a krabby patty. This is a reference to the YouTube video of a drunk David Hasselhoff lying on the ground, eating a hamburger.
Chosen answer: You need to provide a little bit more information to be able to answer a question like this. In what region is it not being shown? I see it being replayed here in Australia fairly frequently. As for a general reason, there does not appear to be any for why it specifically might have been taken off the air in any country or region. Like any show certain episodes can sometimes not be replayed for long periods for unknown reasons.