It's not things that upset us but our judgements about things. - Epictetus

For my part, I can say, ‘bring what challenge you please and I will turn it to good account: bring illness, death, poverty, slander, a judgement of death: they will all be converted to advantage by my wand of Hermes.

But I want power and renown so that I may help other people,” you say. What do you mean by “help”? Can you really give them happiness and satisfaction — things that are in their own spheres of power, not yours?

Look now, this is the starting point of philosophy: the recognition that different people have conflicting opinions, the rejection of mere opinion so that it comes to be viewed with mistrust, an investigation of opinion to determine whether it is rightly held, and the discovery of a standard of judgement, comparable to the balance that we have devised for the determining of weights, or the carpenter's rule for determining whether things are straight or crooked.