Because you like Mona Vanderwaal in Pretty Little Liars
If Lisbeth Salander can hurt a bastard who deserves it by digging up stuff about him, she feels good. See them in The Girl with the Dragon Tattoo.
Deadpool thinks life is an endless series of train wrecks with only brief commercial-like breaks of happiness. See them in Deadpool.
Frodo might have carried the ring, but Samwise Gamgee carried the ring bearer. See them in The Lord of the Rings.
Satine cynically gives up on love so she can advance her singing career. But she meets a dreamer who reminds her there's more to life than ambition. See them in Moulin Rouge.
M. Bison is a diabolical megalomaniac hell-bent on dominating the world. See them in Street Fighter.
A kind and funny valedictorian, Gwen Stacy likes to make out with Spider-man when her homework's done. See them in Marvel Cinematic Universe.
Basil Hallward is dominated, soul, brain, and power by Dorian. See them in Dorian Gray.
Anger-filled, merciless, and tortured, Kylo Ren is always at war—with the Rebel Alliance, and with himself. See them in Star Wars Series.
Bucky Barnes used to be a good-hearted American soldier. Now he's the cold-hearted Winter Soldier. See them in Marvel Cinematic Universe.
Clary Fray's philosophy: dive into the supernatural underworld first and ask questions later. See them in City of Bones.
Poison Ivy is a seductive, venomous botanist laments the fact that there are so many people to kill, yet so little time. See them in DC Extended Universe.