Don’t mistake your assumptions for the truth. - Epictetus

In the long run, every man will pay the penalty for his own misdeeds. The man who remembers this will be angry with no one, indignant with no one, revile no one, blame no one, offend no one, hate no one.

With every accident, ask yourself what abilities you have for making a proper use of it. If you see an attractive person, you will find that self-restraint is the ability you have against your desire. If you are in pain, you will find fortitude. If you hear unpleasant language, you will find patience. And thus habituated, the appearances of things will not hurry you away along with them.

If you would cure anger, do not feed it. Say to yourself: 'I used to be angry every day; then every other day; now only every third or fourth day.' When you reach thirty days offer a sacrifice of thanksgiving to the gods.