Because you like Ishmael in Moby Dick
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.
Don't worry about this forensic scientist offing you unless you're a serial killer yourself. (You're not, right? Just checking.) See them in Dexter.
John Watson is haunted by his past (who isn't) but he's starting to branch out with some help from a world class detective. See them in Sherlock.
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.
Nancy Wheeler is popular but independent, sheltered but gutsy. See them in Stranger Things.
For now Lindsay Weir is a geek, but who knows? Maybe she fits in better with the freaks. See them in Freaks and Geeks.
Sebastien Michaelis is a demonic butler who approaches life with effortless finesse and a diabolical streak. See them in Black Butler.
He's a get rich or die tryin' kind of raccoon. See them in Marvel Cinematic Universe.
Chaos is what killed the dinosaurs, and there's nothing Jason "J.D." Dean loves more than chaos. See them in Heathers.
For the sake of science, Kurisu Makise will persevere no matter how deep into the dark secrets of the world she finds herself. See them in Steins;Gate.
Stanley Barber is a loveable goofball with impeccable (if eccentric) fashion sense, unique music taste, and a wealth of strange but useful knowledge. See them in I Am Not Okay With This.