OK, it's not really a song but I consider that I am allowed to break the rules at my own funeral; and anyway: I can't choose a song for a funeral. That really would make it seem as if a single song could sum up a person.
I could ask people sit through thirty-two songs. Followed by selections from Green Ideas perhaps?
Or rather than that, the people at my funeral - if there is a funeral - if there are any people there - could listen to this piece and rather than think about me could contemplate the simple and strange perfection and precision that is Mozart. Is there any music more beautiful than his?
I have self-indulgently chosen a sad piece.
A confession: many years ago I used to have this Sonata on tape and listened to it often, and it never occurred to me that there were two pianos (blush). The whole piece made a lot more sense when, eventually, I found out.