Because you like Klaus Heissler in American Dad!
She's mostly doom and gloom, but you'd get nowhere without Sadness. See them in Inside Out.
Nemo is a small fish in a vast ocean, but he dreams of seeing it all. See them in Finding Nemo.
Walter White's knowledge of chemistry allows him to cook astoundingly pure meth, leading to a rapid – albeit tumultuous – rise in the criminal drug world. See them in Breaking Bad.
Daria Morgendorffer is so defensive that she actively works to make people dislike her so that she don't feel bad when they do. See them in Daria.
Tarzan is walking the line between human and animal. Good thing he has excellent balance. See them in Tarzan.
We defy you to find a man who's ever been cooler while simply saying his own name. See them in Casino Royale.
Don't worry about this forensic scientist offing you unless you're a serial killer yourself. (You're not, right? Just checking.) See them in Dexter.
Alison DiLaurentis believes you're always better off with a really good lie. See them in Pretty Little Liars.
Willow Rosenberg may be a witch who can defeat the forces of evil, but she still gets emotional over kittens on the Internet. See them in Buffy the Vampire Slayer.
A natural leader, Clarke Griffin dispenses both justice and mercy, and she does it all while being selflessly humble. See them in The 100.
Damon Salvatore used to miss being human. Now he can't think of anything more miserable. See them in The Vampire Diaries.