The media is a big influence showing photoshopped and flawless images of celebrities. Talking about more 'adult' topics to a younger audience.
People always want to do what they can't. Teens are still underage to do certain things.
They want to do what they want when they want to, which is what they think that adults do, however they don't want to have to face the consequences.
I think independence is the overriding factor here. Teens want independence because they are just a little bit too young to completely have it.
A slogan idea could be..... Independent me.