My biggest piano frustration: I can't drink as much as Art Tatum!
Yeah, I think I've got that part of Tatum's and Waller's diet down pretty good, even after a long time of just drinking beer, mostly. Less fattening than the
good hard stuff! Also less drunkening, but that's OK for now.
Unfortunately, those two heavyweights had extraordinary improvisatory skills, whereas I'm just stuck with a bad memory and mediocre ability to cover up rough spots in European "art music" with improvisation. Doesn't seem to affect playing blues or general American "roots" music or some not-too-cerebral jazz, much, but it's a problem elsewhere. And, in fact, a ton of jazz standards or just plain "standards" I can only fake through if I haven't played it in years. Jazz or even rock tunes is a pretty big book of tunes to remember some subtleties unless you play and rotate all them most days, which I haven't done in at least a few years. You never forget completely, but they get a little foggy as time goes by, no matter how good the ear can "fake" a forgotten bridge or turnaround.
So, memory for holding, say, a dozen pieces I'm working on in mind (trying all the tricks in the book to extend memory and learning to cover each piece in entirety [e.g., dividing pieces into discrete "blocks," practice away from the keyboard using snippets of the score, incorporating aural memory in a conscious way, even down to writing mnemonics on a whiteboard using Roman Numeral analysis above the keyboard, etc.]), while trying to retain some basic repertoire that I technically "know" (or have known) that I like to keep as back-up. There's a lot of those that I can play a page or two from, but it still takes some small effort to keep even that as I get older.
ETA For "old repertoire" that I can supposedly play, but struggle to remember, from Brahms, the B minor Rhapsody, the Eb minor Intermezzo from Op. 118, or, for that matter the A major intermezzo from the same. Many of the Beethoven Op. 126 (I've resorted to printing four pages on one page on scans from my favorite edition, the Brendel ed. from Wiener). Some Chopin Waltzes or Nocturnes. You know, those ones you "know" but after a few twenty-four bar segments, you forget the rest. Or insert any number of other pieces — I've gotten better at remembering the Bach Partita in E minor, the fugue, but at many places in the supposedly improvisatory-like Toccata-like sections, I either have to make something up.. Likewise many other sections of the same partita, like the Sarabande or the Corrente: enough to get it going, but not enough to remember all the way through. (NOT the Gigue: I've given up on that). I think I might be retarded, but it's rare I can even remember much beyond the first half if the "Air." That's part of why I like the Sinfonie of Bach: while one can get tired of the music, there's not the pressure to play them all from memory, even though, like the WTC, they're pedantic pieces, but like Chopin's Préludes, they're also little jewels of music.
The rest of my own problems is that I know pretty well how to fix moments of musical "stuttering" over certain passages, down to noting specific measures of various pieces to drill, revising uncomfortable fingerings, but after I spend a week of writing down great plans of attack, something else in life comes up and I forget my resolve to stick to my plans, and just play the music in the easiest way possible. Namely, just sight-reading through and noting..."Hmmm...I should fix that. Oh well, water's boiling, time for a coffee break!"