Yes! Definitely one for working out the stresses of the day!!! (But only to be played after a serious warming up...I can only stretch a 9th so can really hurt myself if I get too carried away without the old scales, arpeggios, Hanon etc first...)

Great thing to say! I often have the feeling I also "half-learn" pieces and so when I "drop" them, I set myself the task of playing them again after a few weeks and make a note of this in my diary, etc. But very often that day never comes ... so I leave the piece there. I have noticed I have to love a piece to be able to have the necessary stimulus to repeat it infinitely until it becomes a "permanent possession" (an expression I read in a book on piano playing). Maybe one should move on to other pieces as variety is also important but for some months one should not completely leave aside the previous one(s) entirely. This would be a fit topic for another discussion as I believe many of us are "affected" by this syndrome ...