Because you like Nina Sayer in Black Swan
Sideshow Bob is a bitter ex-performer who was forced to do inhumane stunts for slapstick comedy. Now he's exacting revenge on his former boss, a clown. See them in The Simpsons.
You won't like him when Bruce Banner is angry. See them in Marvel Cinematic Universe.
Although Jareth seems like he's just a harmless romantic, his powers make him a formidable foe. See them in Labyrinth.
Thanos is an intergalactic warlord, on the hunt for infinite power. See them in Marvel Cinematic Universe.
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.
Margaery Tyrell is one of the most adept and charming liars there is. See them in Game of Thrones.
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.
Christian Grey is just as controlling in the bedroom as the boardroom. See them in Fifty Shades of Grey.
Michael Moscovitz is a high school student of few words but a lot of heart. See them in The Princess Diaries.
Wanderer is a Soul, a parasite sent into a host to take over their body, extracting information from them and colonizing their species. See them in The Host.
Stefan Salvatore was the golden boy when he was alive. Can he keep it up as a vampire? See them in The Vampire Diaries.