I was in a relationship with a classical pianist for a time. Debbie was the great love of my life. Losing her nearly finished me. Some times I miss her still. She could also often be completely psychotic. I don't miss that.
In any case, I spent thousands of hours listing to her practice. From finger exercises to committing long pieces to memory to playing and practicing all that she had learned. She even taught me to do a duet with her one Christmas.
My favorite piece of classical piano then, as now, was Waltz in C Sharp Minor by Chopin. Debbie played it to perfection although probably not quite as well as Vladimir Horowitz who performs it here.