Because you like Michael Myers in Halloween
Princess Bubblegum is brilliant and determined, but can display a nasty temper. See them in Adventure Time.
Dolores Umbridge keeps her villainy hidden (albeit poorly) behind a sheen of sugary pink politeness. See them in Harry Potter Series.
A reclusive introvert, Liz Sherman has a temper that's literally lethal. See them in Hellboy.
A majestic ruler, Mufasa is respected throughout the animal kingdom. See them in The Lion King.
A cursed pirate captain, Barbossa is greedy, vengeful, and surprisingly cheeky. See them in Pirates of the Caribbean: the Curse of the Black Pearl.
Popular jock Andrew Clark is pretty bizarre. He's just better at hiding it, that's all. See them in The Breakfast Club.
Driven and straightforward with high-technology parts, EVE was sent to Earth to see if it is habitable. See them in WALL-E.
Morticia Addams hates anything bright and cheery and loves all things ghoulish, ghastly, and violent. See them in The Addams Family.
Danny Zuko's car is auto-matic. Its system-matic. Its hyyyyydro-matic. Why, its greased lightning! See them in Grease.
A bloodsucker, Carlisle Cullen is actually more likely to give you a blood infusion. See them in Twilight.