8. Rocky's Missing Number Two
This one is a blink-and-you-miss-it continuity error. Early on in the film, Rocky's gym manager, Mickey, comes by his apartment to convince the boxer to let him train him. This is an emotionally loaded scene with the two men getting into a heated argument. But, what you might not have noticed is that someone stole Rocky's number two.
Specifically, it's the number two hanging on Rocky's apartment door. When Mickey arrives, it's on the door, but when he exits the apartment, it's suddenly gone. The same thing happens with a dart stuck in Rocky's bathroom door. So, either Rocky is haunted by the netherworld's laziest poltergeist or the world;s most particular burglar. Or the set director screwed up.
Take your pick.