Learning a new piece is such a fun, interesting, and educational process. You start off mainly learning the notes, and then you begin to learn all the subtle details in the music.
It takes so much investment of time, energy, and the mind to fully learn it. And yet you never stop learning; you never stop revising your technique and the carefulness of the dynamics and emotion you’re using.
Every time you play it, you’re playing it for the first time that way. I think that is part of what makes it so special.