The only reason I haven't gone completely insane while locked up in my apartment is this:
Chopin's Fanstasie Impromptu in C# Minor
(Wait through the long pause at the beginning)
As always, my first reaction is sadness and frustration that a piece I used to KILL when I was a child is now completely beyond my skills. Because this is such a technically demanding piece, I can't just fake my way through the entire piece. I need to relearn it much the same way that I learned it in the first place: endlessly repeating single measures at a time until my fingers, hands, wrists and arms cooperate. (Thank goodness for my digital piano and earphones, or I'd have been kicked out of my apt a long time ago).
And it's precisely because the piece is so insanely difficult, that I am able to practice it at all. If it were any easier, I'd fake my way through it a few times until I deem it "good enough" (although, not "good" by any measure) and move on with my life.
But "good enough" is NOT enough for this piece. For a very simple reason: in order to play it AT ALL, you have to know it almost perfectly. This piece doesn't lend itself to being faked.
And so it's a single measure at a time. Thinking about playing the piece as a whole would leave me utterly discouraged at the impossibility of the feat. This is the only piece I've ever played that HURTS me to play. My wrists and forearms ache from it, and I am reminded of one performance long ago when I had played it with a bad cut on one fingertip - the scab opened and I bled freely on the keys. (Yes, I know, disgusting - but it was perhaps the only time my piano teacher was truly proud of me [albeit being a little grossed out at the same time]).
It makes me happy that I am still capable of this kind of focus. Or perhaps I should say that I am happy that I am again capable of this kind of focus. I'm not fantasizing about the goal of being able to play the whole piece. There's no big picture in mind. It's just me and a single measure, alone in that one moment.