Because you like Biff Tannen in Back to the Future
R2-D2 has been in the galaxy saving business for decades. Not bad for somebody whose vocabulary is limited to "beep-boop." See them in Star Wars Series.
It's a mad, mad world, but Alice has a surprisingly level head as goes her own way down the rabbit hole. See them in Alice in Wonderland.
Park feels like an outsider everywhere he goes, but he doesn't know if he wants to try fitting in anymore. See them in Eleanor and Park .
Shaun is used to being lazy. And now, you're asking him to fight for his life? See them in Shaun of the Dead.
A dedicated hedonist, Jack Harkness appreciates raunchy stories, stiff drinks, and excellent bottoms. See them in Doctor Who.
Empathetic Nausicaa embraces all forms of life, even those that might scare other people. See them in Nausicaa of the Valley of the Wind.
Hans Landa doesn't seem to have issues with Jews, but he hunts them because he's determined to do his job well. See them in Inglourious Basterds.
A house elf, Dobby is loyal, compassionate, and yearning for freedom. See them in Harry Potter Series.
There is never a dull moment with Jim Moriarty: expect booze and sing alongs in between all of the homicide. See them in Sherlock.
Artemis Fowl understands the way of the world. If he wins, he's a prodigy. If he loses, then he's crazy. That is how history is written. See them in Artemis Fowl.
Walter White's knowledge of chemistry allows him to cook astoundingly pure meth, leading to a rapid – albeit tumultuous – rise in the criminal drug world. See them in Breaking Bad.
If Lisbeth Salander can hurt a bastard who deserves it by digging up stuff about him, she feels good. See them in The Girl with the Dragon Tattoo.