Because you like Ender Wiggin in Ender's Game
Lyra Belacqua is prone to getting in trouble, but she's also clever enough to get out of it. Most of the time. See them in The Golden Compass.
Stuck on a lifeboat with zoo animals without food and fresh water, Pi Patel uses his intelligence to face the greatest test of all: survival. See them in Life of Pi.
The Warden of the camp says that digging holes in the desert builds character, but Stanley Yelnats suspects there's more to it. See them in Holes.
A tough tomboy with a protective streak, Maximum Ride is a human-bird hybrid. See them in Maximum Ride.
Cassie Sullivan is resilient and resourceful, but she's not quite as brave as she pretends to be. See them in The 5th Wave.
Tarzan is walking the line between human and animal. Good thing he has excellent balance. See them in Tarzan.
Arthur Dent is an incredibly normal man on an incredibly abnormal adventure. See them in The Hitchhiker's Guide to the Galaxy.
Cinder has been beaten down by the world, but she's learning that her cyborg abilities are pretty helpful. See them in Cinder .
Gruff and sarcastic, Detective Harry Dresden use unconventional ways to track down perps, including using magic and the supernatural. See them in The Dresden Files.
Faced with inequality, Gale Hawthorne has a rebellious spirit that only grows. See them in The Hunger Games .
Even the smallest person can change the course of the world, if he's brave enough. See them in The Lord of the Rings.