Source: John Sellars, Stoicism (Berkeley: University of California Press, 2006) 3.
"Nevertheless the result is a powerful summary of Stoic practical philosophy, and the opening chapter perfectly captures the essence of Epictetus' philosophy as we know it: 'Of things, some are up to us, and some are not up to us. Up to us are opinion, impulse, desire, aversion, and, in a word, all our actions. Not up to us are body, possessions, reputations, offices and, in a word, all that are not our actions' (Ench. 1.1)...Almost all human misery, [Epictetus] argues, is the product of people not understanding the nature and significance of this division, of assuming that they have control of things that in fact they do not, of grounding their happiness in external things 'not up to us' and so making it highly vulnerable to the vicissitudes of fortune. Instead, we should ground our happiness on those things that are 'up to us', on those things that can never be taken away from us. If we do that, our happiness will be literally invulnerable."
Epictetus was a first century C.E. Stoic philosopher. His philosophy reminds me of the Serenity Prayer and Buddhism. The Serenity Prayer says, "God, grant me the serenity to accept the things I cannot change, the courage to change the things that I can, and the wisdom to know the difference." And Buddhism seeks to free people from desiring the unstable things of life, telling them that they can control their reactions to events rather than allowing the events to eat on them.
My problem is that I can't really distinguish between the things I can change and the things I can't. If someone is rude to me, is that my fault, or is it because he has issues? Or could it be a little of both? Do I have to feel responsible if not everyone on the face of the earth likes me, even if they may dislike the way that I am--something I'm partially responsible for?