Because you like Buttercup in The Princess Bride
The brilliant and well-adjusted Ender Wiggin is being groomed for the next generation of military leaders to fight alien invaders. See them in Ender's Game.
Never shy about sharing what she thinks, Beatrice loves to make smart remarks and keep men on their toes. See them in Much Ado About Nothing.
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.
Motivated by a strong sense of curiosity, fleet-footed Lina Mayfleet is happiest when she's on the move. See them in The City of Ember.
Smart but insecure, Tally Youngblood is torn between what she wants and what her society demands. See them in Uglies.
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.
A responsible kid, Hugo Cabret is still capable of flights of fancy. See them in Hugo.
Cinder has been beaten down by the world, but she's learning that her cyborg abilities are pretty helpful. See them in Cinder .
Sabriel is smart enough to understand the dangers that await her and brave enough to face them anyway. See them in Abhorsen Series.
Daisy Buchanan is beautiful and rich, and seems to have it all. But beneath the glitter and the glam, things are more complicated for her. See them in The Great Gatsby.
Stranded on Mars, Mark Watney is armed with quick wits, an electronic diary, disco music, and an undying resolve to make it back. See them in The Martian.