It is enough if everyone does well what he or she is supposed to do. - Epictetus

What is the first business of one who studies philosophy? To part with self-conceit. For it is impossible for any one to begin to learn what he thinks that he already knows.

Because you think of yourself as no more than a single thread in the robe, whose duty it is to conform to the mass of people – just as a single white thread seemingly has no wish to clash with the remainder of the garment. [18] But I aspire to be the purple stripe, that is, the garment’s brilliant hem. However small a part it may be, it can still manage to make the garment as a whole attractive. Don’t tell me, then, ‘Be like the rest,’ because in that case I cannot be the purple stripe

Disease is an impediment to the body, but not to the will, unless the will itself chooses. Lameness is an impediment to the leg, but not to the will. And add this reflection on the occasion of everything that happens; for you will find it an impediment to something else, but not to yourself.