Wisdom is the supreme part of happiness.

Of everything that goes into a good life, judgment counts for the most, and it is one of the few parts not handed out by temperament or luck. Knowing which things deserve your worry, which people deserve your time, and which battles are not yours spares you a good deal of avoidable misery. Hardship brings its own unhappiness, and no amount of wisdom cancels that. A fair share of the rest comes from giving ordinary events the wrong size of reaction, and getting the proportions right is a skill that improves.

After the next everyday thing that upsets you, ask how much it will matter in a year. If the answer is not much, you have found a place where better judgment would buy back real hours.