Because you like Meggie Folchart in Inkheart
Helena is a mentally unstable, childish, and completely merciless. And most of all, she's an unstoppable killer. See them in Orphan Black.
A karate master/rocket scientist/squirrel, Sandy Cheeks is the only one who can clean up the other resident's messes in Bikini Bottom. See them in SpongeBob SquarePants.
Luke Skywalker always wanted to leave home, but he didn't expect that it would be as part of a quest to rescue a princess and save the galaxy. See them in Star Wars Series.
A super-soldier, Master Chief might be more machine than man. And for humanity's sake, thank God. See them in Halo.
An adventurous dreamer, George Bailey always winds up putting other people's dreams first. See them in It's A Wonderful Life.
A secret smoker, Margot Tenenbaum has plenty more secrets where that came from. See them in The Royal Tenenbaums.
George Weasley likes to invent quirky joke products, play Quidditch, and cause poor Mrs. Weasley a lot of anxiety. See them in Harry Potter Series.
A no-nonsense pro, Agent K has dedicated his whole life to his job. See them in Men in Black.
With those dearest to him dead and no one to trust, Max Rockatansky is a slightly hysterical man alone on the run in a post-apocalyptic world. See them in Mad Max: Fury Road.
Catwoman might be slightly unhinged, but you can't say this feline villainess isn't confident. See them in DC Extended Universe.
A photographic memory is just one of many skills Lexie Grey brings to the table as a surgeon. See them in Grey's Anatomy.