Because you like Billy Costigan in The Departed
The Hastings family is old and powerful, and Spencer will do anything to continue excelling. See them in Pretty Little Liars.
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.
Milo Thatch is an enthusiastic researcher without cynicism. See them in Atlantis: The Lost Empire.
Steve Stifler is more than just a dude with a hot mom. He's also rude, profane, and obnoxious. See them in American Pie.
Victor Frankenstein can create life, so he's pretty awesome if he says so himself. See them in Frankenstein.
Beware! Anton Chigurh carries a coin with him, which he forces his victims to flip to decide whether they will live or die. See them in No Country for Old Men.
Gruff and efficient, Sam Fisher protects a nation that can never admit he exists. See them in Tom Clancy's Splinter Cell.
It's a race against time to develop his theory of the origins of the Universe before Stephen Hawking's body and mind give out. See them in The Theory of Everything.
He may forget his homework, lose his toad, and fall off brooms, but Neville Longbottom can also single-handedly destroy villains. See them in Harry Potter Series.
Donkey Kong is a strong, banana-loving, and caring uncle to Diddy Kong. See them in Donkey Kong.
It's time somebody has to take over. It might as well be Fish Mooney. See them in Gotham.