8. Hayden Christensen
George Lucas pretty much single-handedly gave Hayden Christensen a career and he's been ruining what might have been decent movies without him ever since. For some reason Lucas thought Hayden would be the perfect guy to show us how Anakin Skywalker made the transition to being Darth Vader, the greatest villain any galaxy has ever known. And all despite the actors significant lack of any acting ability. Why did he do this to us? Were there incriminating photos involved and blackmail? We can only guess. Hayden Christensen moped through two underwhelming Star Wars prequels and almost ruined how we perceive Darth Vader. And then not only did he ruin the Star Wars prequels but he had a perfectly good chance to kick off another franchise with Jumper and killed it by emoting like a lump of wood. Huge potential just washed down the drain. Somehow Hayden manages to keep on going as he has 5 films in production right now. Thanks again George... really.