“[I]f you set out to mention everything you would never be done, and that's what counts, to be done, to have done. Oh, I know, even when you mention only a few of the things there are you do not get done either, I know, I know. But it's a change of muck. And if all muck is the same muck that doesn't matter, it's good to have a change of muck, to move from one heap to another, from time to time, fluttering you might say, like a butterfly, as if you were ephemeral.”