That's a pretty amusing story.
I remember going into a fast food place when I was just a few weeks sober (and, needless to say, not exactly in possession of all my marbles, nor in good control of my emotions), and I flipped out on the poor server who messed up my order. A few days later I felt really bad about it. Not to the point of tracking the server down and apologizing, but I realized it really was a crappy way to talk to someone, however badly they messed up.
The really amusing part is that if you'd told this guy you were only there to support your friend, he probably would have pegged you as an alcoholic in denial, lol.