That was until I recorded myself playing on a piano AND recorded a good piano student playing on the same piano, with the same recording device. Then I listened back to it with good speakers.
Boy, was that a revelation.
Yeah, it would be, right?!
I wish when I were younger (say from young teenager/tween to maybe age 22 or so) I had the stones to apply The Recording to my own playing (highly encouraged by my best and longest-term "legit music" piano teacher, but duly ignored by me, even though I was already using a 1/4" open-reel machine to slow down jazz solos, so I had the technology!), and also foreign language things would have been nice.
I have since made any number of recordings, even just through onboard sequencers, or things from defunct live band concerts, but I must say, it's become such an effort. I don't bother anymore: it's just an unnecessary hassle.
I feel as though I have good enough context and experience to know what I sound like. Although it still is something I have done in the past few years to check the tempo, and make sure I'm still metronomically within a reasonable range doing just improvised "American" music. It's easy to inadvertently slow down or even speed up if it's familiar material one has done a million times and is not paying attention....because of....reasons. Basically not paying attention while playing,
The worst is trying to record video+audio with a phone or a small tablet: it's incredible to me that everyone but me seems to be able to find the right tripod (or piece of duck tape/gorilla glue) to get the right angle. That's well beyond me.
That was until I recorded myself playing on a piano AND recorded a good piano student playing on the same piano, with the same recording device. Then I listened back to it with good speakers.
I'm interpreting as that you acquited yourself very well in the comparison.
If so, congratulations! Most times in the past (not, in my case, doing comparisons, just improvised music) I've been somewhat gratified by what is minimally acceptable playing on my part.