“If you are distressed by anything external, the pain is not due to the thing itself but to your own estimate of it; and this you have the power to revoke at any moment.”
Marcus Aurelius

If you haven’t taken a look at Marcus Aurelius’s “Meditations,” it’s a quick read of wisdom put together by the last of the “5 Good Emperors” of the Pax Romana. Suppose we were to wipe the slate clean but for one tool we could keep to guide us through the rest of life, mine would be emotional mastery. It seems like that was important to the emperor as well.
In the above quote, Aurelius recognizes that there is a difference between “what happened” and “your estimate of what happened,” though we often conflate the two. Emotional mastery is the ability to separate the occurrence from the estimate and then to endow the occurrence with whatever meaning you choose or as he says, “revoke” a painful meaning.
For example, suppose you are an artist trying to sell your painting, but no one buys it. That is “what happened,” the distressing external event. Your estimate of that event maybe that you are a poor artist and you should listen to your parents and “give up.” If you believe in your art, you have the ability to revoke this meaning at any moment! You have the power to decide what meaning the event had so as not to cause you any undue pain. The meaning you choose could be as simple as “it’s raining outside and no one had the opportunity to even see your painting, much less purchase it.”
Therefore, recognize your power to choose whatever meaning that takes away pain and gives you pleasure.