Simon

“Your happiness depends on three things, all of which are within your power: your will, your ideas concerning the events in which you are involved, and the use you make of your ideas.”
― Epictetus, The Art of Living: The Classical Manual on Virtue, Happiness, and Effectiveness

“The greatest obstacle to living is expectancy, which hangs upon tomorrow and loses today. You are arranging what lies in Fortune’s control, and abandoning what lies in yours. What are you looking at? To what goal are you straining? The whole future lies in uncertainty: live immediately.”
― Seneca, On the Shortness of Life

“No one could endure lasting adversity if it continued to have the same force as when it first hit us. We are all tied to Fortune, some by a loose and golden chain, and others by a tight one of baser metal: but what does it matter? We are all held in the same captivity, and those who have bound others are themselves in bonds - unless you think perhaps that the left-hand chain is lighter. One man is bound by high office, another by wealth; good birth weighs down some, and a humble origin others; some bow under the rule of other men and some under their own; some are restricted to one place by exile, others by priesthoods: all life is a servitude.

So you have to get used to your circumstances, complain about them as little as possible, and grasp whatever advantage they have to offer: no condition is so bitter that a stable mind cannot find some consolation in it.”
― Seneca, On the Shortness of Life: Life Is Long if You Know How to Use It

“It is not that we have a short time to live, but that we waste a lot of it. Life is long enough, and a sufficiently generous amount has been given to us for the highest achievements if it were all well invested. But when it is wasted in heedless luxury and spent on no good activity, we are forced at last by death’s final constraint to realize that it has passed away before we knew it was passing. So it is: we are not given a short life but we make it short, and we are not ill-supplied but wasteful of it… Life is long if you know how to use it.”
― Seneca, On the Shortness of Life: Life Is Long if You Know How to Use It