Because you like Norman Bates in Psycho
Hank McCoy is a quintessential nerdy scientist but with a few rather unconventional physical attributes. See them in X-Men Series.
Just call Jeff Lebowski The Dude. Or His Dudeness, Duder, or El Duderino if you're not into that whole brevity thing. See them in The Big Lebowski.
A monstrous pirate captain, Davy Jones is quite literally heartless. See them in Pirates of the Caribbean: the Curse of the Black Pearl.
This cannibalistic villain may be a loner, but Killer Croc doesn't have problems with self-confidence. See them in Suicide Squad.
A company man who has never done a day of work, Creed Bratton pursues sketchy extracurricular activities that keep him busy. See them in The Office.
Jack's big imagination is never limited by his incredibly cramped surroundings. See them in Room.
The "runt" of his biker gang, Tetsuo Shima grapples with a perpetual inferiority complex. See them in Akira.
Evan is a sensible kid, but being sensible isn't going to help him lose his virginity. See them in Superbad.
It turns out Dracula's son Alucard has some pretty severe daddy issues. See them in Castlevania.
Holden Caulfield is convinced that the whole adult world is full of phonies. See them in The Catcher in the Rye.