Because you like Olive Snook in Pushing Daisies
After having his mind altered after a bad breakup, Joel Barish is not convinced that ignorance is bliss. See them in Eternal Sunshine of the Spotless Mind.
Breaking bones and hearts, Callie Torres has figured out how to put the bones back together. But the hearts? Not so much. See them in Grey's Anatomy.
Wanderer is a Soul, a parasite sent into a host to take over their body, extracting information from them and colonizing their species. See them in The Host.
Kara "Starbuck" Thrace will beat you in cards, drink you under the table, then fly circles around you in her fighter plane. See them in Battlestar Galactica.
Frederick Frankenstein is an eccentric (O.K., maybe a little insane) professor who is excited to be delving into his family's past. See them in Young Frankenstein.
It turns out the girl of your dreams just might have dreams of her own. See them in (500) Days of Summer.
Cinderella will sacrifice herself to keep her family's memory alive. See them in Cinderella (Live Action).
Stubborn, impulsive, and fun-loving, Hallie Parker is not afraid to devise some schemes to bring her family together. See them in The Parent Trap.
A suave womanizer, Jacob Palmer has turned seduction into a science. See them in Crazy, Stupid Love.
Count Olaf is a traveling actor, except he can't act and his homicidal tendencies make finding work pretty difficult. See them in Lemony Snicket's A Series of Unfortunate Events.