12. Ashton Kutcher
Worst Performances: My Boss's Daughter (2003), The Butterfly Effect (2004), The Guardian (2006), What Happens In Vegas (2008)
Admittedly, it's hard to like a guy on screen when he's such a nuisance off. Whenever he's on talk shows, Kutcher carries himself with a holier-than-thou attitude, which would be easily dismissible if the guy showed ample talent in his movies. But, alas, he does not. In comedic mode, he's typically loud and overbearing (see: What Happens In Vegas); when trying to stretch himself into dramatic fields, he's unable to shed his natural I'm-the-man aura (see: The Butterfly Effect). Frankly, his acting career peaked with his funny work on That '70's Show, and that ended way back in 2006.