Lou Reed, 'Perfect Day' ('Trainspotting,' 1996)
"'Perfect Day' was known as such a sublime, beautiful song, which it clearly is, so there's no point in trying to reemphasize that directly," says Boyle. "So we thought we'd do the opposite of that and use it completely ironically in the grimiest part of the estates of Scotland in the worst moment of the overdose scene. We carry these songs with us. So you try and say: I know it's in your head. But try and see your favorite, favorite song used like this. Go on, then . . . "