Because you like Jack Torrance in The Shining
A monstrous pirate captain, Davy Jones is quite literally heartless. See them in Pirates of the Caribbean: the Curse of the Black Pearl.
Jack Skellington is a nightmare-man with a soft heart and smooth voice. See them in The Nightmare Before Christmas.
Eugene H. Krabs is a greedy restaurant owner who won't let a dime out of the reach of his claws. See them in SpongeBob SquarePants.
For Wreck It Ralph, it's not easy being the bad guy. Especially when you've been designed to destroy but really desire love. See them in Wreck-It Ralph.
Raphael is a short-fused hothead who loves a good fight and some tasty pizza. See them in Teenage Mutant Ninja Turtles.
The self-described "ghost with the most" knows the ins-and-outs of specter life like no other. Just ask him. See them in Beetlejuice.
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.
Simon Belmont is a vampire hunter bravely carrying on the family business. See them in Castlevania.