It's never nice to be disappointed by a reliable or well loved actor, but even Hollywood royalty have their bad days. Most viewers cringed at Leo DiCaprio's uniquely ill conceived turn in notorious cult flop The Beach, while many fans will never forgive Charlize Theron for Sweet November. Luckily, this sort of regrettable surprise is rare. After all, a decent hit-maker in Hollywood can usually be depended on to make savvy career choices and to light up screens with their talent. Sometimes an even rarer phenomenon occurs, though, in the form of a much more welcome surprise. A terrible actor, universally panned and relied on to produce material that's trite at best and unwatchable at worst, will pleasantly shock audiences with a memorable and commendable performance. At such a potentially career-defining moment, a flailing actor's future rests tenuously on the brink of greatness. It can go either way. The actor might capitalise on this moment of inspiration, and forge his or her way into the golden streets of Hollywood nobility; Matthew McConaughey is modern cinematic history's best example of this. Or, as unfortunately proved the case with the following ten actors, they'll let the spark of hope flicker and die, only to return to the next misguided script or vapid plot. The following ten roles promised great things of these otherwise maligned actors, and their movies live on in cinematic history as testament to careers that could have been.