18. John Leguizamo
Worst Performances: Super Mario Bros. (1993), The Pest (1996), The Happening (2008), Vanishing On 7th Street (2011)
If nothing else, John Leguizamo should be applauded for his diversity. The once-full-time stand-up comedian has dabbled in pretty much every film genre; now if he could just find one that he's consistently good in, we'd be straight. Until then, though, we're forced to acknowledge his lack of discernable fortitude on screen. Unless he's playing a movie's wisecracking comic relief, Leguizamo repeatedly gets overpowered by roles that call for emotional weight or steely presence. Can acting teachers double as personal trainers?