5. Malcolm McDowell - A Clockwork Orange
Considered by many to be the quintessential Stanley Kubrick film, "A Clockwork Orange" is set in a dystopian future, where the adolescents of the world freely roam the streets, beating up on other gangs and raping women as they please. It is a disturbing insight into the possibilities of a youth gone wrong. And this is made all the more clear by Malcolm McDowell's fantastic portrayal of Alex DeLarge, the "hero" of the film.
In the most famous scene, Alex DeLarge is strapped to a chair, fed intravenous drugs meant to give him nausea, and forced to watch dirty and violent movies, with the idea that he would form an association between the nausea and the violence. His head was held in place with a metal machine, and his eyes forced open with sharp instruments. As a result of this scene, McDowell actually suffered serious injuries to his eyes, scratching his cornea and even becoming temporarily blind.
I suppose it's not technically the actor's fault, considering that the scene was created by director Stanley Kubrick. But I would be at least slightly upset if my own day-to-day job consisted of machines stabbing and scratching at my eyeballs. Maybe it was worth it just to have been able to work with such a legendary director.