The Stoic philosopher Epictetus was born around 55 A.D. in the Greco-Roman town of Hierapolis, present-day Pamukkale, Turkey. The first line of Epictetus’ manual of ethical advice, the Enchiridion, is "Some things are in our control and others not"; being a Stoic means interrogating those flashes of dread or anticipation asking whether they apply to things outside your control and, if they do, being "ready with the reaction: Then it’s none of my concern."
Much of Epictetus’ advice is about not getting angry at slaves. At first, I thought I could skip those parts. But I soon realized that I had the same self-recriminatory and illogical thoughts in my interactions with small-business owners and service professionals. Epictetus shook me with this simple exercise: "Starting with things of little value—a bit of spilled oil, a little stolen wine—repeat to yourself: For such a small price, I buy tranquillity."