I've been reading, slowly and intermittently, Antifragile: Things That Gain From Disorder. It's about the curious fact that some things grow stronger when faced with a stress. Your muscles, for example, need resistance in order to grow strong; if you lie in bed for a month they atrophy. Then there's the Hydra, who grew two new heads each time one was lopped off.
Not that I want to be a Hydra. But y'know, it would be handy to go a step further than bouncing back from difficulty, and grow stronger.
I was having a hard time processing some of the book, until the author pointed out that the situations in which antifragility is possible are quite specific. Too much stress for too long a time is harmful; you must have a period of recovery or rest in which to process what has happened and prepare for the next stage. Chronic stress -- whether situational, like eternally rough finances, or self-imposed perfectionism -- is almost always destructive. After all, if you work out in the gym all day every day your muscles get exhausted rather than stronger. It's the break that allows for regrouping, progress, increased strength.
Most of us, I think, imagine inner strength is something we either have or don't-have. The idea that stress could be good for us is distasteful: it means we have to go through difficulty. Worse, it means we have to take responsibility for how we respond to stress, because we actually have a choice (of sorts) when it comes to what to do with it. We can cave, we can persevere, or we can continue looking for growth.