Keep in mind that it isn’t the one who has it in for you and takes a swipe that harms you, but rather the harm comes from your own belief about the abuse. So when someone arouses your anger, know that it’s really your own opinion fueling it. Instead, make it your first response not to be carried away by such impressions, for with time and distance self-mastery is more easily achieved.

Epictetus

Enchiridion, 20 via The Daily Stoic