People are not disturbed by things, but by the view they take of them. - Epictetus

Some things are in our control and others not. Things in our control are opinion, pursuit, desire, aversion, and, in a word, whatever are our own actions. Things not in our control are body, property, reputation, command, and, in one word, whatever are not our actions. The things in our control are by nature free, unrestrained, unhindered; but those not in our control are weak, slavish, restrained, belonging to others. Remember, then, that if you suppose that things which are slavish by nature are also free, and that what belongs to others is your own, then you will be hindered. You will lament, you will be disturbed, and you will find fault both with gods and men. But if you suppose that only to be your own which is your own, and what belongs to others such as it really is, then no one will ever compel you or restrain you. Further, you will find fault with no one or accuse no one. You will do nothing against your will. No one will hurt you, you will have no enemies, and you not be harmed.

Take the example of a public speaker. He is confident that he has written a good speech, he has committed the thing to memory, and can deliver it smoothly. Still he agonizes, [6] because it’s not enough for him to be competent, he also hungers for the crowd’s approval.

In time, you will grow to be confident that there is not a single impression that you will not have the moral means to tolerate.