Actual content of the movie. Have you ever seen it? It may just disturb me more than you. I've found others not to have been moved by movies, shows or stories which I had previously thought were fundamental enough to speak to everybody.
It may be that I identify personally with the movie. I felt what I figured all the characters feel, that there is this heavy fear that is deep in the back of their minds that everything they do during the course of the movie was going to come to a catastrophic end. A high itself is a metaphor for that movie. You feel fantastic while on the high but you know that at some unknown point in the future it is going to lead to some kind of a crash or hangover, but in the case of requiem for a dream, the crash is their lives and they have no way of knowing how bad the hangover will be. Something drug users can't totally shake is the knowledge that their lifestyle cannot last forever even if they push that reality deep into the back of their mind. All of their lives are so nasty and pathetic with disturbing backgrounds like troubled childhoods, that when they crash it makes their lives even more of a depressing failure.
The one that really disturbs me is mrs goldfarb. But I have an issue with amphetamine psychosis, it disturbs me. I imagine what it must be like to be frustrated, afraid, and confused in the world of the schizophrenic and it seems like the worst kind of nightmare, and one that you cannot EVER wake up from because it is HOW your brain works now. No way to die happy from there. Although sick as it is, she probably is the happiest one of them all at the end.
When I listen to a song I essentially watch whatever movie it plays in. I cannot listen to the sound track without watching the movie in my head.