Because you like Duke Nukem in Duke Nukem
Mystique is a shape-shifting mutant who, after too many disappointments, does not want to co-exist with humans. See them in X-Men Series.
The son of Death has an obsession with perfection and symmetry. See them in Soul Eater.
Edward Elric has a quick mind along with a quick temper. See them in Fullmetal Alchemist.
While he might be too cool for school, Soul isn't too cool to do the right thing. See them in Soul Eater.
His murderous megalomania aside, Loki is quite charming. Just don't mention his strapping older brother; he's a tad jealous. See them in Marvel Cinematic Universe.
Belle has ready every storybook in town, and she's slowly realizing that life is no fairytale. See them in Beauty and the Beast.
A daring conman, Flynn Rider is so charismatic that you might not mind when he steals from you. See them in Tangled.
Larger than life and wealthy beyond measure, Willy Wonka is more than a titan in the sweets industry; he is an arbiter of taste. See them in Charlie and the Chocolate Factory.
Everyone Barney Stinson knows is getting married or pregnant. But he's just getting more awesome. See them in How I Met Your Mother.
Howl puts the "tortured" in tortured artist. He just wants to be recognized for his work, but no one wants to trust a boy that sorta looks like a bird. See them in Howl's Moving Castle.
It doesn't matter how noble or brave he is. Jon Snow is a bastard, and people don't let him forget it. See them in Game of Thrones.