Because you like Wendy Testaburger in South Park

Cinder has been beaten down by the world, but she's learning that her cyborg abilities are pretty helpful. See them in Cinder .

Rose Hathaway is a reckless, rebellious smartass who's training to be a royal vampire guardian. See them in Vampire Academy.

Will Herondale is an emotionally distant bad boy with a secret. See them in Clockwork Angel .

Faced with inequality, Gale Hawthorne has a rebellious spirit that only grows. See them in The Hunger Games .