Because you like Arthur Fonzarelli in Happy Days
A reclusive introvert, Liz Sherman has a temper that's literally lethal. See them in Hellboy.
Donna is boisterous and spunky traveller of the TARDIS, exploring worlds beyond the simple mundane enterprises of Earth. See them in Doctor Who.
Milo Thatch is an enthusiastic researcher without cynicism. See them in Atlantis: The Lost Empire.
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.
Shaggy might be a bit of a slacker, but his heart and his stomach are usually in the right place. See them in Scooby-Doo.
Henry Mills is an idealistic young boy with the heart of the truest believer. See them in Once Upon a Time.
A brave but pessimistic nobleman, Boromir knows one does not simply walk into Mordor. See them in The Lord of the Rings.
Philip J. Fry accidentally cryogenically froze himself for a millennium. See them in Futurama.