7. Zach Galafianakis
After around a decade of working as a relatively unmemorable supporting actor, Zach Galifianakis finally got his big break playing Alan in 2009's The Hangover. Though he was hilarious, the impression is that the guy is a comedian, not an actor; he's good at playing the crazy weirdo, but he plays it safe and clings desperately to that shtick, perhaps aware of his limitations as an actor. We're still waiting for the movie to prove that he can actually act rather than just live off the goodwill he earned with his hilarious turn in The Hangover. Given that he's returning to our cinema screens in 2 months for Part III of the saga, it's unlikely he's going to shed that image anytime soon. While from a financial perspective he might as well rinse the persona for as long as he can, cinemagoers are going to get bored with him once they realise he's just a one-trick pony, and as a result, not a very good actor at all. Would I go see the guy do stand up? Absolutely. But do I get enticed by his movies? Not in the slightest.