> I have observed it in myself, time and time again. If not it directly, something similar enough. [Emphasis added by me] This is the crux. I agree with you th

> I have observed it in myself, time and time again. If not it directly, something similar enough. [Emphasis added by me] This is the crux. I agree with you that there are certainly some sort of effects related to will-power, self-control, focus, energy levels, and so on. This feels obvious enough, based on everyday experience. But it seems we don't yet know how to isolate, measure, or analyze these dynamics in a highly rigorous way. Of course, there is possibility that the everyday experience is actually by caused some different mechanism we don't understand yet.