Because you like Granny Weatherwax in Discworld
Good fashion? Check. Snarky quips? Check. Supernatural evil-fighting powers? Also check. See them in Buffy the Vampire Slayer.
A level-headed show business icon despite his amphibian status, Kermit is the brains behind the success of the Muppets. See them in The Muppet Movie.
Princess-turned-General Leia Organa is a sharp, fearless royal who gets herself into trouble and fights her way out of it. See them in Star Wars Series.
Whether he's fighting or flirting, Jace Wayland is all swagger. See them in City of Bones.
Nick Fury is an enigmatic, manipulative, and eye-patched director of the Avengers Initiative. See them in Marvel Cinematic Universe.
The son of Death has an obsession with perfection and symmetry. See them in Soul Eater.
A plucky 13-year-old with a flair for the dramatic, Kiki is a witch in training. See them in Kiki's Delivery Service.
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.
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.
Steven Universe is an excitable youth who likes junk food and trying to save the world. See them in Steven Universe.
While he might be too cool for school, Soul isn't too cool to do the right thing. See them in Soul Eater.