Why Are Japanese Kids So Polite?

A friend visiting Japan messages me: I find it very interesting that a lot of bogan (dumb) Australian (and dumb American parents too) will always excuse their children’s poor behaviour in public saying things like “boys will be boys,” “you know what kids are like at that age” whereas I come here to Japan and walk around and the children of all ages are incredibly well behaved, not rowdy, respectful, etc. It is such a refreshing change from walking through a food court in Australia and seeing hordes of feral children running around and their parents just rolling their eyes while their little darlings scream incessantly.