When I was asked this question at some point during an interview I strangely enough named the d’Albert concerto. Objectively seen this is by far not the best nor the most beautiful piece of cello literature, but I was working on it at that time and it was the first piece shooting through my mind. The in my eyes most important cellist Mstislav Rostropovich answered the same question, as I found out later, with the explanation to my strange answer: he always likes the piece best he is playing in the moment - almost like an actor who ideally identifies with each role he is playing in such a way that he becomes the role; in order to give justice to any piece of music, we should at least in the moment of the performance feel it as our favorite piece. I see it as a defeat whenever I am being told after a concert that I played well but that the piece wasn’t good. In this case I have failed as a performer.