Because you like Cindy Brady in The Brady Bunch
Although Penny's friends have genius-level IQs, they regularly come to her for advice and insight. See them in The Big Bang Theory.
Whether it's randomly bursting into song or writing Nancy Drew fan-fiction, Jess proudly marches to the beat of her own drum. See them in New Girl.
Marty McFly is a skateboarder, aspiring rock star, and reluctant time-traveler. See them in Back to the Future.
Everyone Barney Stinson knows is getting married or pregnant. But he's just getting more awesome. See them in How I Met Your Mother.
Korra is stubborn, outgoing, and faced with huge responsibilities she might not be ready for. See them in The Legend of Korra.
Cher Horowitz may have a problem with hubris, but she looks utterly fabulous while learning a lesson about the dangers of meddling. See them in Clueless.
An All-American football player, a ping pong star, and a freakishly determined runner, Forrest Gump has a ton of stories to tell. See them in Forrest Gump.
Flexibility is more than Helen Parr's superpower. It's a key tenet of her personality that allows her to be both firm and understanding. See them in The Incredibles.
Charlie Kelmeckis is a wallflower who's starting to blossom into something more. See them in The Perks of Being a Wallflower.
Percy Jackson is an ordinary student thrust into the world of myth come alive. See them in Percy Jackson & The Olympians: The Lightning Thief.
A dreamy space cadet, Luna Lovegood has never met a conspiracy theory she didn't believe in. See them in Harry Potter Series.