Growing up.

I often hear statements from my friends that go something like "Yeah, but he's something like a real adult..."

I don't know where this came from, but I think people who are of my (our) age feel something like we're not quite real adults yet. That there's this small subset of people who are in their early to mid twenties who are adults, and then there's the rest of us who are just masquerading as such, and eventually we'll either grow up or be found out.

I wonder what it is that makes us feel not quite like adults. Is it us, or is it the way we were raised, or the way society treats us, or something else altogether?

Really, I'd like some opinions on this.