Because you like Natasha Rostova in War and Peace

A suave demon, Crowley grants humans their wishes in exchange for their soul, only to find loopholes that benefit him. See them in Supernatural.

Krusty The Clown somehow makes life sillier and more somber at the same time. See them in The Simpsons.

England may cultivate the image of a well-bred gentleman, but he has both the temper and mouth of a seasoned sailor. See them in Axis Powers Hetalia.

He's a troubled insomniac in search of a moment to rest and a meaning to his existence. See them in Fight Club.

A born psychopath, don't expect Michael Myers to understand the difference between right and wrong. See them in Halloween.

Given his ability to wrench street signs from the ground, Shizuo Heiwajima is a useful one to have in dangerous Ikekuburo. See them in Durarara!!.

Philip J. Fry accidentally cryogenically froze himself for a millennium. See them in Futurama.

A crabby troll, Karkat Vantas is perpetually angry about his lot in life. See them in Homestuck.

Convinced that the world is conspiring against him, Tatsuhiro's reconciled himself to his fate as a shut-in. See them in Welcome to the NHK.

Insightful about everyone else's neuroses, Rose Lalonde is not as aware of her own. See them in Homestuck.