Serial killers: Reprehensible, disgusting... movie stars? It's true. Audiences have always loved to root for the bad guy: There's nothing that leaves you feeling as wicked -- or conflicted -- in the theaters than to find your attention drawn to the villain. Yet because glorifying a serial killer outright would be reprehensible, movie killers are always given a secondary motivation, one that allows the audience to identify with these anti-heroes in a way that we wouldn't even bother to do in real life.

Take, for example, Hannibal Lecter, aka Hannibal the Cannibal. While Silence of the Lambs introduced him to us as both monster and hero, In Hannibal, he manages to be both at the same moment when placed against the vengeful pedophile Mason Verger (Gary Oldman) and the duplicitous FBI agent Paul Krendler (Ray Liotta) in Hannibal. Sometimes, Lecter proves, people need to be eaten for the greater good. (Note too that although we see him cooking, we never watch him actually dining.)

Christian Bale's Patrick Bateman in American Psycho has a completely different motivation. Though the movie version of Bateman doesn't go nearly as far as his literary version, he kills, maims, and chainsaws his way through the '80s. Acting on these violent urges give him a rush of emotion that's otherwise missing in his superficial life. A metaphor of the times, Bateman should seem reprehensible, but instead. comes off as an almost cartoonish exaggeration of the repression of the American Male. Plus, it's entirely possible he may have imagined everything.

Then there are Mickey and Mallory Knox, from Natural Born Killers. Their carnage is born first out of necessity (Mallory is being abused by her father) and then as an indictment against the complacency of America, and the exploitive news media. And they're not completely cold-blooded: They spare Mallory's brother, and feel remorse when they accidentally kill the wrong person.

Think you know what a hero is? Test your beliefs against the good doctor. Check out a full schedule of Hannibal on AMC here.

And to see some more villains on film, go to our slideshow.