Last Wednesday and Thursday during piano practice things just clicked. It seemed like time had slowed slightly so that for every note my fingers were just waiting there to play and I could concentrate on how I was playing rather than getting the notes right, even at full tempo. The music was "under my fingers" and I was looking forward to the lesson on Friday. Then, for reasons I won't go into, I didn't get a lot of sleep on Thursday night. Friday morning was fine but by the afternoon I was beginning to flag . . .
. . . and then I went to my piano lesson. Oh dear. It felt like a disaster. Nothing went right, not scales, not arpeggios, not the pieces, nothing. However, my teacher was quite happy: Under the pressure of being tired the cracks in my technique had become much more obvious, making her job much easier As a performance, it was a disaster but as a lesson it was nothing of the sort.
It just goes to show, nothing is completely useless - it can always be used as a bad example!