This is *awesome*, because it concretely explains a phenomenon that's driven me crazy for years but I've never been able to put my finger on - why, after a very productive day, I feel more drained than accomplished. It would seem to be because the exhaustion from making so many choices outweighs the satisfaction from getting them done.
Now to see if managing the number of choices I have to make in a day will mitigate that effect at all.