We do not succeed in changing things according to our desire, but gradually our desire changes. The situation that we hoped to change because it was intolerable becomes unimportant. We have not managed to surmount the obstacle, as we were absolutely determined to do, but life has taken us round it, led us past it, and then if we turn round to gaze at the remote past, we can barely catch sight of it, so imperceptible has it become.