I once learned how to play The Weakerthan's "Leash" on piano. It took me a few hours of a furiously depressed day, alone in my mother's house. My parent's bought my sister and I a nice piano when we were young. It's gone relatively unused since then. Pictures of our youth line the top and there is probably some sort of small lamp. Every so often when I come home, I try and bang out something engaging and fresh. It becomes a new method of brain exercise, accessing a part that hasn't entirely withered, rather sagged to a point of atrophy where it may not be worth the effort and attention to reinvigorate the mental muscles required to effectively play the piano. But it is fun, and it makes me feel productive. So I spend a day learning a song that I will soon forget. That's an ok thing to do.