Much like how after you’ve lifted weights to the point of fatigue your arms won’t function very well, after you’ve used your mind to the point of fatigue—be it to resist temptation, make tough decisions, or work on challenging cognitive tasks—it, too, won’t function very well. This fatigue might lead you to eat cookies, give up on solving a tough intellectual problem, or even prematurely give in during physical challenges. In the worst case, you might even cheat on your significant other.
