Because you like Tom Paris in Star Trek Voyager
Drusilla's hobbies include dolls, music, and killing people. See them in Buffy the Vampire Slayer.
Victor Frankenstein can create life, so he's pretty awesome if he says so himself. See them in Frankenstein.
Edmund Pevensie isn't a bad person, but he did sell his siblings out for a tin of Turkish Delight. See them in The Chronicles of Narnia.
Nicholas Angel is super-dedicated to his job as a police officer. Maybe a little too dedicated. See them in Hot Fuzz.
Donna is boisterous and spunky traveller of the TARDIS, exploring worlds beyond the simple mundane enterprises of Earth. See them in Doctor Who.
A monstrous pirate captain, Davy Jones is quite literally heartless. See them in Pirates of the Caribbean: the Curse of the Black Pearl.
On the outside, Gwen seems meek and calm. But she has an inner core of steel. See them in Merlin.
Frank Reynolds is too gross even for the prostitutes he hires. See them in It's Always Sunny in Philadelphia .
James Wilson is a compassionate doctor who willingly plays the sidekick. See them in House M.D..
Gruff and sarcastic, Detective Harry Dresden use unconventional ways to track down perps, including using magic and the supernatural. See them in The Dresden Files.
A majestic ruler, Mufasa is respected throughout the animal kingdom. See them in The Lion King.