I was with my violin teacher.  Before we started my lesson, she asked me if I had contacted "Bobby" yet.  Bobby apparently was a pianist who was to accompany me in a concert.  I realized to my chagrin that she had asked me this more than once before, and I kept forgetting to do it, and now the time for the concert was very close.  I was really embarrassed, but I had to tell her that I had not contacted him, and furthermore, I couldn't participate in the concert because I did not play the violin well enough, having not taken in lessons in 45 years or having played the violin since then.  I said I didn't want to embarrass her or myself by ruining the concert.  She was not happy, obviously, and had to start thinking of someone else to take my place on short notice.