Because you like Arnold in Hey Arnold!
David Nolan is a noble fairy tale prince with the heart of a hero, regardless of whether he can remember his past or not. See them in Once Upon a Time.
Frank Reynolds is too gross even for the prostitutes he hires. See them in It's Always Sunny in Philadelphia .
A meek schoolteacher, Mary Margaret Blanchard can't remember her past as a spirited, swashbuckling Snow White. See them in Once Upon a Time.
Caleb Rivers is a bad boy with a good reason for acting out. See them in Pretty Little Liars.
Louise Belcher might be just a kid, but she can manipulate just about anyone with a pulse. All in the name of fun, of course. See them in Bob's Burgers.
C is for cookie, and that's more than good enough for him. See them in Sesame Street.
Eric Forman's interests include smoking weed, collecting Luke Skywalker memorabilia, eating Fatso burgers, and making his dad mad. See them in That '70s Show.
Philip J. Fry accidentally cryogenically froze himself for a millennium. See them in Futurama.
