Every comment here seems to be trying to analyse this film. Don't. It is a sickening film. The whole premise that a man (and you could probably have inserted a woman in a similar role) can purposely go and commit such emotional horror is soul destroying. that's what makes this such compulsive viewing. There can't be a person out there who hasn't at one point deliberately taken an action that has had similar repercussions. Emotionally cruelty is the worst cruelty of all.
The performances are straight out of reality and when coupled with the direction it made me feel that I was a fly on the wall. That's what hurt. Chad's character is not over-the-top as suggested elsewhere in here. You can pick a Chad out in plenty of places. Unfortunately the stereotyped male leads (superstud and nerdy) spoil the film a bit and whilst a deaf girl isn't exactly a character you can despise, her deafness becomes increasingly irrelevant as the film goes on (as seen by the emotional bonds that develop between the nerd and Christine).
Ultimately it doesn't say anything about the male psyche or relationships, but it does show an extreme version of the kind of emotional cruelty of which we are all capable.