No one gets this movie.
From reading all the threads on this page it seems to me that no one gets it.
Crystal and Jamie are not opposites - they are both self indulgent. Crystal is a complete hypocrite - shown many times - but thrown in the face of the less intelligent when she drinks the soft drink after lecturing the others about sugar. We never know what she did to the women in the park to piss them off - but from her character it seems likely that their anger is reasonable.
Jamie invites hookers to his friend's house without permission, invites a stranger on their planned trip without asking, steals the cactus etc...
The real contrast is between the Chileans and the yanks. The Chileans are relaxed and down to Earth whereas the yanks are busy disappearing up their own backsides. This continues even under the influence of the drug, showing how deeply ingrained it is.
The biggest disappointment to me about this movie was the fact it never made me so much as smile, let a lone laugh. Maybe because I have met all these people before, way too many times...