The most successful element of the movie, by far (save for the incredible music and the way it fits the mood / style perfectly) is the portrayal of drug use.

The first time we watch the characters take heroin is a rush for the viewer. Pop, wizz, shunk. A dozen 2 second clips of imagery: the spark of the flame, heroin on a microscopic level liquifying, the flow of fluid, the sound of the sigh and a groan of pleasure, a closeup of pupils dilating at an extreme rate... and then two men my age having fun. Enjoying themselves - experiencing pleasure and closeness and a bond.

No needles, no blood - nothing icky.

The reaction it gets is that is so cool. If from those 20 seconds the movie doesn't manage to show you precisely why heroin (and drug use in general) has appeal you're missing the main point of the movie.

...and every single time they shoot up for the rest of the show the sequence is identical. Nothing is changed. Every time the visual fireworks have less and less effect on the viewer. You become desensitized to it. You keep reminding yourself what it was like seeing that for the first time and being oh so impressed... but the repetition gets you a little down - nothing is ever like that first moment of ecstacy.

I have never seen a film so capable of portraying precisely what drug use is all about. How natural it becomes. How it seeps into your life. How it becomes routine. How it connects and in many cases drives friendships... and how much searching there is to find that first time epiphany all over again.