1. Most of the film is pure, insane fun - There is a skeleton-thin plot, very little character development and absolutely ridiculous scenarios but I have to admit that it was really fun to watch. It moved rather quickly, had an extremely appealing soundtrack and I laughed out loud several times. If you just take the film at face value and join the party - you should have a good time.
2. The ending of the film was not - The party was bordering on dangerous but still really funny until the last part (you know when fires and riots started breaking out and endangering the lives of the surrounding neighbors - including the newborn baby across the street). The fact that there are no big consequences for anyone was just plain dumb and the part that annoyed me the most was that the kids father had a moment of pride in his son's ability to cause mayhem. I'm sorry to be the voice of reason, but if they live in a house like that in Pasadena (i.e a multi-million dollar home) - they obviously have money. People who have money, care about money - there is no way that his father would be so calm about losing everything.
3. People are fucking stupid - I was in complete shock when the film ended and people in the theater started clapping. It wasn't a film that was deserving of applause. It was completely unoriginal (some described it as Superbad on crack, which I think is insulting to Superbad - but they did flat out copy the 3 main characters and somehow made them not interesting at all). I feel bad for you if you think this was something to cheer for.