Protect your peace
Principle 12 from the Enchiridion
Solve the problem without giving it the rest of your day. Small annoyances do not have to cost you the calm needed to deal with them.
Original Passage
If you want to improve, reject such reasonings as these: "If I neglect my affairs, I'll have no income; if I don't correct my servant, he will be bad." For it is better to die with hunger, exempt from grief and fear, than to live in affluence with perturbation; and it is better your servant should be bad, than you unhappy.
Begin therefore from little things. Is a little oil spilt? A little wine stolen? Say to yourself, "This is the price paid for equanimity, for tranquillity, and nothing is to be had for nothing." When you call your servant, it is possible that he may not come; or, if he does, he may not do what you want. But he is by no means of such importance that it should be in his power to give you any disturbance.
Modern Interpretation
Epictetus says that calm has a price. We cannot expect to stay composed while also demanding that every small thing go our way.
The practice begins with minor annoyances. That does not mean ignoring a problem. It means dealing with it without handing your mood over to it. If your peace requires flawless service and perfect timing, almost anything can take it away.
In Practice
Your food arrives late, and part of the order is missing. You can explain the problem and ask for a refund without treating the person answering the message as your sworn enemy.
The problem can still be fixed. What changes is this: you do not have to carry the irritation through the rest of your evening.
Reflection Question
Which small annoyance ruins your mood most easily? Can you deal with it without letting it take over?