I went down to the OSC to play the piano and passed what was apparently a guitar lesson. I popped my head in to listen, because the student was trying to play van morrison's "moondance". At the piano, I played around with it a bit. It's a pretty nice, simple chord progression to play over. Later the instructor happened to leave the building through the dance platform area where the piano is, so I resumed "moondance", and he chuckled. But then he pointed out that the B7 I was playing in one of the turnarounds really ought to be a B7b9b13, and the F#7 a Fm7b5. It sounds so much better with those changes! Hooray for random chord snob passersby.