Ask yourself: Does this appearance (of events) concern the things that are within my own control or those that are not? If it concerns anything outside your control, train yourself not to worry about it.

Don't just say you have read books. Show that through them you have learned to think better, to be a more discriminating and reflective person. Books are the training weights of the mind. They are very helpful, but it would be a bad mistake to suppose that one has made progress simply by having internalized their contents." Translation by Sharon Lebell

It is difficulties that show what men are.

You may fetter my leg, but Zeus himself cannot get the better of my free will.

So you wish to conquer in the Olympic Games, my friend? And I, too... But first mark the conditions and the consequences. You will have to put yourself under discipline; to eat by rule, to avoid cakes and sweetmeats; to take exercise at the appointed hour whether you like it or not, in cold and heat; to abstain from cold drinks and wine at your will. Then, in the conflict itself you are likely enough to dislocate your wrist or twist your ankle, to swallow a great deal of dust, to be severely thrashed, and after all of these things, to be defeated.

No man is free who is not master of himself... Is freedom anything else than the power of living as we choose?

Difficulties are things that show a person what they are.