Regarding "But he doesn't behave like an adult!" - he's only 21, I'd say he acts about as sensible as quite a number of 21 year olds in this world. But seriously, why would I want everyone in the game to act like an adult? That would be dull. Even "fun loving" ones, you still need the less sensible people to shake things up. I can't think of a single Final Fantasy game I've played where everyone acted like an adult and I still found them all great. I wouldn't say Snow acts like a child, either, though. He acts like someone who is desperate to prove himself (to himself as much as anyone else) and encourage others. I think there's a lot more to Snow than most people think, because they focus too much on the parts you see throughout the majority of the game. Vanille gets similar treatment.