3. Billy Bob Thornton in 'Bad Santa' (2003)

As Willie, an alcoholic, potty-mouthed, self-loathing safecracker whose mall-Santa gig is just an excuse to case the joint, Thornton does just about everything possible to desecrate the character and the holiday, but even he finds a measure of miraculous seasonal redemption. Despite Willie's extreme naughtiness, Thornton's hilarious, go-for-broke performance makes him one of the screen's most memorable Clauses.