Because you like Sandy Cheeks in SpongeBob SquarePants
Kyoya Ootori is possibly the only person who could reasonably go from VP of a school club to ruling the world. See them in Ouran High School Host Club.
WALL-E is a quirky little romantic robot cleaning the wasteland known as Earth. See them in WALL-E.
Korra is stubborn, outgoing, and faced with huge responsibilities she might not be ready for. See them in The Legend of Korra.
Light Yagami has a plan to make a better world, and morals won't stop him. See them in Death Note.
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.
Wei Shen is an undercover cop on a mission for justice (or at least vengeance). See them in Sleeping Dogs.
Charming and enigmatic, Amy Dunne takes her love for puzzles to a cunning new level. See them in Gone Girl.
Courteous, dangerous, and powerful, Kaname Kuran controls an entire court of vampires. Very, very pretty vampires. See them in Vampire Knight.
When the going gets tough, Dre Johnson gets tougher. Well, he'd like to think he does. See them in Blackish.
Betty Cooper seems like a sweet girl, but she also has a dark side and can go beyond what's safe or sane. See them in Archie Comics.
Brilliant, violent, and only a little insane, the Joker doesn't listen to anyone except the voices in his head. See them in DC Extended Universe.