Because you like Emmett Brown in Back to the Future
Ellen Ripley defines the word "badass." When she's not leading her crew on an interstellar voyage, she's slaying terrifying creatures. See them in Alien.
A caring, curious, and considerate android, Vision could crush your skull if he had to. But he'd rather not. See them in Marvel Cinematic Universe.
For Celty Sturluson, it's rather upsetting to be the only headless girl in a city filled with full-bodied humans. See them in Durarara!!.
Years of brutal winters, foreign invasions, and crippling loneliness have left Russia's mental state far from wholly intact. See them in Axis Powers Hetalia.
A brilliant "extractor," Dom Cobb has spent the past few years running from the authorities and his inner demons. See them in Inception.
Quinn Fabray can become a monster when there is something she wants. See them in Glee.
Foul mouthed and disturbingly comfortable with violence, Hit-Girl is a precocious assassin who doesn't need anyone's protection. See them in Kick-Ass.
This suave con-man doesn't just want to become rich. Danny Ocean wants to rip off the guy who stole his wife in the biggest Vegas con. See them in Ocean's Eleven.
Beware! Anton Chigurh carries a coin with him, which he forces his victims to flip to decide whether they will live or die. See them in No Country for Old Men.
Charles Xavier is a telepath who believes mutants and humans are both good at heart and can live in harmony. See them in X-Men Series.
Cosmo Kramer is an eccentric schemer whom you might know better as the "Assman." See them in Seinfeld.