“Here’s a lesson to test your mind’s mettle: take part of a week in which you have only the most meager and cheap food, dress scantly in shabby clothes, and ask yourself if this is really the worst that you feared. It is when times are good that you should gird yourself for tougher times ahead, for when Fortune is kind the soul can build defenses against her ravages. So it is that soldiers practice maneuvers in peacetime, erecting bunkers with no enemies in sight and exhausting themselves under no attack so that when it comes they won’t grow tired.”