Everyone loves a bad guy. Well, until they get boring. There's nothing worse than watching one of your favorite shows or movies and coming to the conclusion that you just can't stand seeing the baddie anymore. It rarely has anything to do with the actor; they're just trying to make the screenplay work. More often than not, villains who've worn out their welcome are a product of filmmakers getting away from what was good about the character in the first place.
Villain fatigue occurs when someone like Emperor Palpatine, Freddy Krueger, or Lex Luthor keeps coming back even after they've been defeated. They don't change or grow, they just keep trying to take over the galaxy/get revenge on the children of Elm Street/stop Superman, and their attempts at evil grow more outlandish with every iteration.
All of the following villains are great in their initial outings - it's just that they all stayed at the party for a little too long. Remember to vote up the villains that stuck around a bit too long.