Because you like The Man in Black in The Princess Bride
Aang is already a master airbender and once he learns to manipulate water, earth, and fire, he'll be truly unbeatable. See them in Avatar: The Last Airbender.
The personification of America is all about superheroes, hamburgers, and spreading democracy and justice. See them in Axis Powers Hetalia.
Tracy Turnblad's got rhythm, and she's determined to share her dance moves with the world. See them in Hairspray.
Napoleon Dynamite loves tater tots, mythical beasts, and reveling in his awkwardness. See them in Napoleon Dynamite.
Bella Swan thinks of it as her job to help her parents and protect her friends, even though it often ends up the other way around. See them in Twilight.
Kenzo Tenma would have never guessed that ten-year-old he saved would later become a deadly serial killer intent on "thanking" him. See them in Monster (TV Show).
Elena Gilbert is the quintessential girl-next-door who gets involved with the new "boy" at school. See them in The Vampire Diaries.
A jaded skeptic who only wants to get paid, Garrett becomes involved in bigger struggles that force him to be less self-serving. See them in Thief.
Suzaku Kururugi defeats enemies with his flashy but deadly jump kicks. But he's willing to sacrifice himself for peace. See them in Code Geass.
Po is a clumsy, friendly panda who likes to take it easy. But now he's expected to save the world? See them in Kung Fu Panda.
Whether it's randomly bursting into song or writing Nancy Drew fan-fiction, Jess proudly marches to the beat of her own drum. See them in New Girl.