Because you like Khan Noonien Singh in Star Trek Into Darkness
Count Olaf is a traveling actor, except he can't act and his homicidal tendencies make finding work pretty difficult. See them in Lemony Snicket's A Series of Unfortunate Events.
A malevolent dark wizard, Voldemort is so fearsome that he's known primarily as "He Who Must Not Be Named." See them in Harry Potter Series.
Merciless and manipulative, Queen Ravenna is determined to become the fairest of them all. See them in Snow White and the Huntsman.
Manipulative, conniving, and ruthless, Mr. Gold is enigmatic no matter what world he's in. See them in Once Upon a Time.
After years of living vicariously through other people's heroic stories, Wade Watts is about to become a hero himself. See them in Ready Player One.
The destroyer, Drax lives for one thing and one thing only: revenge. See them in Marvel Cinematic Universe.
Relentlessly cheery Ned Flanders enjoys a nice piece of bread with water on the side for dipping See them in The Simpsons.
As a doctor-in-training, John Dorian should have his head in the game. But most of the time, it's in the clouds. See them in Scrubs.
Foggy Nelson is a principled small-time lawyer fighting for fellow little guys. See them in Marvel Cinematic Universe.
Peter Venkman's "research" projects are designed to get undergraduate students to sleep with him. Though it turns out he can bust ghosts. See them in Ghostbusters.
Darcy Lewis is a razor-sharp scientist studying things that science can't explain. See them in Thor.