Because you like Zaphod Beeblebrox in The Hitchhiker's Guide to the Galaxy
Nadine Franklin likes to wallow in her misery almost as much as she likes to torment her mother. See them in The Edge of Seventeen.
Severus Snape is a misanthropic potions teacher with a vindictive streak. See them in Harry Potter Series.
You don't teach a class called "How To Get Away With Murder" without knowing a thing or two about getting away with things. See them in How to Get Away with Murder.
Titus Andromedon will show you the ropes, help you with your problems, and sing at you constantly, whether you like it or not. See them in Unbreakable Kimmy Schmidt.
Noah Calhoun is lost without Allie, who seems to have moved on. See them in The Notebook.
Smart, sarcastic, and loyal, Stiles Stilinski doesn't just want to be the sidekick in someone else's life. See them in Teen Wolf.
People think that because Tris is small, or a girl, or a Stiff, she can't possibly be cruel. But they're wrong. See them in Divergent.
Quentin has his whole life mapped out. It might sound boring, but he likes boring. See them in Paper Towns.
What Ron Weasley lacks in motivation and book smarts, he makes up for in loyalty and street smarts. See them in Harry Potter Series.