9. Sam Worthington
Sam Worthington began life carving out a career as a brick-layer before he managed to end up with a few bit-parts acting, being most acclaimed (in fact, his only acclaimed role to date) in Cate Shortland's aussie flick Somersault. He came to greater worldwide prominence by starring in Terminator Salvation, but the real lucky break he got was working with James Cameron on his ground-breaking blockbuster Avatar. Though Salvation was released first, Worthington was only picked for that role on the recommendation of Cameron, who had already been filming Avatar for a long time before the Terminator film even began production. Needless to say, he's a terrible, wooden actor, who was given the stage to star in what would become the highest-grossing film of all time and the fourth entry to one of cinema's most beloved franchises, all in the space of a year. Worthers has followed it up with a series of underwhelming action films and crime flicks, his bland personality and flat delivery ensuring that his making the grade for Avatar was sheer luck rather than force of will.