" Epictetus was reminded daily how little control he had, even of his own person. As he came to study and understand Stoicism, he adopted this lesson into what he described as our “chief task in life.” It was, he said, simply “to identify and separate matters so that I can say clearly to myself which are externals not under my control, and which have to do with the choices I actually control. "

― Ryan Holiday , Lives of the Stoics: The Art of Living from Zeno to Marcus Aurelius