Because you like Susan Mayer in Desperate Housewives
It's hard to tell if Dean Winchester cares more about saving the world or his 1967 Chevy Impala. See them in Supernatural.
Severus Snape is a misanthropic potions teacher with a vindictive streak. See them in Harry Potter Series.
A wildly brilliant detective, Sherlock Holmes can figure out everything except how to interact with other human beings. See them in Sherlock.
What Ron Weasley lacks in motivation and book smarts, he makes up for in loyalty and street smarts. See them in Harry Potter Series.
An escaped convict on a mission, Sirius Black is brooding, brave, and reckless. See them in Harry Potter Series.
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.
A daring conman, Flynn Rider is so charismatic that you might not mind when he steals from you. See them in Tangled.