Revealing mistake: Jorge misses scanning the barcode on the tire by several inches at the end of the competition, but it rings up anyway.
Continuity mistake: During the scene when Zack sneaks into the cashier's lounge, his buddies are spying on him with a pirate telescope. However when Iqbal hands it to Russell to take a look, the shot is now zoomed in to Zack swiping the card in the slot. This would be impossible as the telescope is fixed to one focal point and was already fully extended for the first shot.
Revealing mistake: Even though the movie is set in the fictional "Super Club" store you can tell it was filmed at a Costco. Some things that give this away include: Kirkland (Costco exclusive brand) products are visible in many scenes, when Dane Cook and Jessica Simpson are talking early in the movie you can see part of the word "Costco" and finally most of the signs and layouts are EXACTLY like a Costco.
Continuity mistake: At Iqbal's son's birthday party when all the guys are around the table playing cards, Russel has his hands free when he talks to Zach about employee of the month. In the next shot, he is holding a beer in his right hand and asks Lon to pass the chips, in the next shot it is back on the table where he picks it up.