Will Power

On my way back to the Cape, Bob Edwards Weekend had a story on Willpower: Rediscovering the Greatest Human Strength by John Tierney and Roy F. Baumeister. Willpower as a 'muscle' in our brains that gets stronger through being exercised and needs glucose to work. Diets don't work because we need to eat to be able to resist overeating.
The same greedy part of the brain does decision making, so judges tend to give parole, a harder decision, earlier in the day. Quarterbacks get decision fatigue.
Personally, I had just gone through hours of decisions on the stuff my mother has been collecting for 50 years. Taking breaks was important.
I loved listening to the section about children who could resist eating a marshmallow, usually by distracting themselves, not by concentrating on defeating the marshmallow. Later studies showed willpower as a prime predictor of success in life, measured in ways like finishing school, marrying happily, and staying out of jail.