“The thing is, a bad feeling doesn’t always mean something is wrong. It just means you’re taxing your body budget. When people exercise to the point of labored breathing, for example, they feel tired and crappy well before they run out of energy. When people solve math problems and perform difficult feats of memory, they can feel hopeless and miserable, even when they are performing well. Any graduate student of mine who never feels distress is clearly doing something wrong.”
