Because you like Eli in Let the Right One In
Princess Bubblegum is brilliant and determined, but can display a nasty temper. See them in Adventure Time.
Liesel Meminger is trying to ease the suffering of those around her, German and Jew alike. See them in The Book Thief.
Optimus Prime is a shapeshifting sentient robot leading a team of robots to stop evil from taking over. See them in Transformers.
When the going gets tough, Rick Grimes gets tougher. It's a very useful trait when the world goes to hell. See them in The Walking Dead.
A natural leader, Clarke Griffin dispenses both justice and mercy, and she does it all while being selflessly humble. See them in The 100.
Wanting more out of life, Pam Beesly has a job she isn't crazy about and is engaged to a guy she's not sure is "The One." See them in The Office.
Freddie Freeman is a superhero aficionado with a dark sense of humor. See them in DC Extended Universe.
Mr. Fox will never truly be happy without a dead chicken between his chompers. See them in Fantastic Mr. Fox.
Some say to survive in Underland you need to be as mad as a hatter–which, luckily, he is. See them in Alice in Wonderland.
Rose Hathaway is a reckless, rebellious smartass who's training to be a royal vampire guardian. See them in Vampire Academy.
A superpowered test subject, Scarlet Witch can manipulate other people's thoughts and force them to confront their worst fears. See them in Marvel Cinematic Universe.