I've met a couple people like that, but it doesn't take long for someone to open their mouth and tell them. Or they realize that they're being treated better than the other guys.
There's this guy at my job who is really cute. He's 16 and everyone is older than him for the most part, but he is so well mannered and has an old soul, so it's easy to forget.
You can tell he knows he's beautiful and people like him, but he is still very humble and has a great personality.