Because you like Stanley Yelnats in Holes
Joey Tribbiani's true passions in life are acting, sandwiches, football, sex, and asking ladies, "how you doing?" See them in Friends.
Billionaire playboy by day and vigilante archer by night, Oliver Queen aims to rid Starling City of crime and atone for his past mistakes. See them in DC Extended Universe.
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.
Norma Bates may look like a harmless housewife, but don't let that fool you. See them in Bates Motel.
Winry Rockbell is an energetic tomboy mechanic with an empathetic streak. See them in Fullmetal Alchemist.
Tina Goldstein is better at getting the job done than following the rules. See them in Fantastic Beasts and Where To Find Them.
A Berlin-based locksmith by day, Wolfgang Bogdanow is a world-class thief by night. He can also see out of other people's eyes, but that's a different issue. See them in Sense8.
N'Jadaka is a righteous man with a violent agenda. See them in Marvel Cinematic Universe.
This master marksman may be a villain, but Deadshot's motives aren't quite as selfish as they seem. See them in DC Extended Universe.
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.