Because you like Frank Costanza in Seinfeld

A wildly brilliant detective, Sherlock Holmes can figure out everything except how to interact with other human beings. See them in Sherlock.

L is enigmatic, child-like, and one of the smartest people in the world. See them in Death Note.

He's an eccentric pirate making it up as he goes along. He's Jack Sparrow, savvy? See them in Pirates of the Caribbean: the Curse of the Black Pearl.