1. Anakin Skywalker - The Star Wars Prequel Trilogy
You had one job, George Lucas, just one: to tell the story of how Anakin Skywalker came to become Darth Vader. The most iconic screen villain of all time, Vader has reached legendary status in the annals of popular culture, as instantly recognisable as any other character from the history of cinema you care to think of. It's hard to know where to begin when it comes to discussing just what it was that went so horribly wrong with the character of Anakin Skywalker in the Star Wars prequel trilogy, but the nine-year-old version in The Phantom Menace is as good a place as any - he might have been entertaining for the younger kids in the audience but for the rest of us he was just plain annoying. Jake Lloyd isn't really to blame, either - no child on the planet (or indeed, in the galaxy) could compensate for such a poorly written and underdeveloped role. Matters hardly improved once Anakin grew up and Hayden Christensen took over the role - from insufferable brat to mopey teenager, any attempt at a degree of complexity in which the balance of good and evil pulled the character to and fro was lost. Referred to as "a good friend" by Obi-Wan Kenobi in the original Star Wars movie, this friendship somehow managed to fail to materialise on the screen. And let's not forget the final embarrassing Darth Vader reveal in the closing moments of the trilogy with the laughable cry, "Noo!" as he inhabits his dark suit for the first time - it's impossible to imagine a potential more outrageously squandered. Lacking charisma and with the emotional range and nuance of a cartoon character, the potentially greatest backstory in the history of cinema became the biggest disappointment of all time. Agree or disagree with the choices on this list? Which potentially great movies do you think have been ruined by a character? Why not post a comment below?