Pallas I would love to hear more!
I have, within reach of the chair I'm sitting in, a (paper) notebook with the titles of about ten pieces I wanted to learn and/or keep in my repertoire, written about two years in. A goal, as it were. I don't play any of them. I can see how having a goal of playing a certain piece might be sufficient to keep someone playing, but not me. Maybe I'm just too fickle, but, heck, learning to play the piano is such a long term process. The horizon is constantly moving. Nowadays I take more of a "let's see what happens" approach.
candela Apart from being absorbed by the music, the act of learning and practicing in itself is what draws me back, not the improvements in ability it leads to. I even try to embrace the struggles and feelings of sometimes being really bad at what I'm doing as welcome life lessons. And I think the music and practice affect my brain and mind in a way that spills over in a positive way on other areas of life, though obviously there's no control for how an alternative present without piano practice would have been. All that's reason and success enough for me to continue practicing.
I think this captures why I keep practicing. Discipline, persistence, the ability to weather set-backs and plateaus--all these teach life skills. And I get to hear and play some wonderful music!