When someone goes in to take a music lesson, both the teacher and the student need to have good manners. Some folks haven't thought much about manners as applied to music lessons, but good manners need attention in the lesson too! And this applies to both the teacher and the student.
I was reminded of this by a recent mandolin student whom I taught for several months. He was apt to do several things that interfered with his learning. Sometimes he wouldn't practice for a week. Sometimes he'd cancel a lesson on short notice, or with no notice at all. But the biggest thing he did to prevent himself from learning was to START PLAYING HIS MANDOLIN, LOUDLY AND FOR A LONG TIME, WHILE I WAS SHOWING HIM A NEW TUNE.
That was not good manners. And it meant, among other things, that (1) he didn't hear me playing and explaining the tune phrase-by-phrase so that he could learn it, and (2) his cute little H4 recorder didn't capture the lesson either, because he was playing at the same time I was. And he didn't know which parts of a tune were going to be hardest to play, because he'd never listened to begin with. Then he'd come in the next week with the tune only half-learned-- and he never did learn many tunes well-- I wonder why.
When you go in to a music lesson, think of all you can do to make the lesson go well. Listen throughout, play when it's your turn, and ask questions. Use good manners.