Because you like Sideshow Bob in The Simpsons
Turanga Leela is the daughter of two mutants who live in the sewers below New York City. See them in Futurama.
Ursula will oh-so-generously grant your wishes for a price. See them in The Little Mermaid.
This lab mouse has one thing on his huge brain: trying to take over the world on a nightly basis. See them in Pinky and the Brain.
This cannibalistic villain may be a loner, but Killer Croc doesn't have problems with self-confidence. See them in Suicide Squad.
Buddy Pine is an unhinged superfan of superheroes using technology to take down his idols. See them in The Incredibles.
A monstrous pirate captain, Davy Jones is quite literally heartless. See them in Pirates of the Caribbean: the Curse of the Black Pearl.
Emma Frost's superpower: transforming her body into an unbreakable diamond. See them in X-Men Series.
Ted is a cursing, smoking, drinking teddy bear who's anything but cuddly. See them in Ted.
Anger is a cantankerous hothead whose job is to get others riled up. See them in Inside Out.
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.
James Gordon happens to be the one guy in Gotham City with proper morals who doesn't also run around in a cape. See them in DC Extended Universe.
This master marksman may be a villain, but Deadshot's motives aren't quite as selfish as they seem. See them in DC Extended Universe.