Limited Willpower
More on decisions, this time about how our ability to make them is actually a finite resource:
Willpower—the popular idea is that it’s something that you use to resist temptation and to make yourself work. But they’ve also found that this same energy is used in making decisions, simply deciding what to have for lunch, what to do at a meeting; all these things deplete the same resource. After a while, when you’ve depleted this resource, it’s a state called ego depletion. You’ve got less self-control, you’re more prone to give in to temptation, it’s harder for you to work, and you tend to make worse decisions.