There is only one way to happiness, and that is to cease worrying about things which are beyond the power of our will
Be on your guard against a false sense of self-importance.
The Art of Living, Epictetus
Keep your attention focused entirely on what is truly your own concern, and be clear that what belongs to others is their business and none of yours. If you do this, you will be impervious to coercion and no one can ever hold you back.
The Art of Living, Epictetus