Whatever you think of him, you have to give it to Phaeton for having big ambitions. When another kid accuses him of not really being the son of Helios, god of the sun, he doesn't take it lying down. He goes to his Mom, Clymene, and demands the truth. When his Mom suggests that he travel to his Dad's distant Palace of Sun to find out for himself, he doesn't shirk from the challenge. Then, when Helios offers him anything he wants in the world, Phaeton doesn't just ask for a life time supply of chocolate or some small fry like that, he says, "Dad, I want to drive your gleaming sun chariot across the sky." Wow, you really can't knock this little demigod for being an underachiever.
Of course, you can knock Phaeton for being a little too full of himself. (Strike that. Make it waaaaay too full of himself.) In fact, over the years, Phaeton has become a symbol of hubris, the Greekalicious word for overweening pride. If Phaeton wasn't so concerned about being cooler than everybody else, he could tell that other kid, "Whatever, I don't care who you think my Dad is. So, nahhh." If he didn't think he was all that and a bag of cheese poofs, he would've heeded Helios's warnings about how dangerous it is to drive the sun chariot, with its wild, flaming horses. Unfortunately for Phaeton, his pride causes his downfall, when he loses control of the horses, and Zeus has to zap him from the sky. In the end, all Phaeton's lofty ambitions wind up in the toilet.