Because you like Doogie Howser in Doogie Howser, M.D.
Caitlin Snow believes that burying herself in science is the best way to save the day or to mend a broken heart. See them in DC Extended Universe.
Alex Danvers is a brilliant engineer tasked with alien threats, and one of those aliens is her adopted sister Supergirl. See them in Supergirl.
Small in stature, Clara Oswald has a big appetite for adventure. See them in Doctor Who.
Patrick Verona is a bad boy who's after a tough girl. See them in 10 Things I Hate About You.
Winston Bishop is sweet, thoughtful, and a little oblivious. And above, he's a loyal friend. See them in New Girl.
Gina Linetti views herself as a sort of life coach/influencer to the rest of the office. She's not so keen on the "work" aspect of her job. See them in Brooklyn Nine-Nine.
Foggy Nelson is a principled small-time lawyer fighting for fellow little guys. See them in Marvel Cinematic Universe.
Harry Osborn is the privileged son of Oscorp's founder with a goblin-sized chip on his shoulder. See them in Marvel Cinematic Universe.
Celie Johnson says she's poor, black, and may even be ugly. But dear God she's here. See them in The Color Purple.
Jesse Aarons' frustration can only find outlet in another world. See them in Bridge to Terabithia.
Danny Zuko's car is auto-matic. Its system-matic. Its hyyyyydro-matic. Why, its greased lightning! See them in Grease.