Representation of Youth in Cinema

Today in cinema youth are depicted in many ways, but a majority of them are negative views. Everyone has a differnt view on youth, to what they do in society, to the age. To me 'youth' is from around 14 to 28/29, most people will go out and party, have fun, act irresponsible - of course there are execptions a lot of the time but TV and media stereotypes youth into this narrowminded view.

I have been watching several films which represent youth:

Attack the Block - Muggers, agressive, rude > nice on the inside and don't really mean any harm.

Human Traffic - Good guys, enjoy a party

Juno - Get preggers, quite mature for the age, responsible (ish) American and not British, could that have an affect?

Trainspotting - Similar to HT just a bit darker, maybe the characters are a little older too

All are from different ares of the world but a marjority are from the UK as that is more representative of the youth cultures I'm looking at. In these films youth is normally looked down upon and the people are taking drugs and/or doing things they are not meant to be doing (mugging people/getting pregnant at 16).