Let us put ourselves in the place of him with whom we are angry. At present an overweening conceit of our own importance makes us prone to anger, and we are quite willing to do to others what we cannot endure to be done to ourselves. (Seneca, On Anger, 3.12)
I am content if I am in accord with Nature in what I will to get and will to avoid, if I follow Nature in impulse to act and to refrain from action, in purpose, and design and assent. (Epictetus, Discourses XXII)
You know how advice is - you only want it if it agrees with what you wanted to do anyways. - John Steinbeck
Advice has value only when the recipient sees themselves as having something to learn. This state of openness, of humility, is so uncommon, the act of giving unsolicited advice will almost always fall on deaf ears. In fact, the obvious intimation, that the recipient does not already know what they need to, that they should be humble and accept this wisdom, is almost always taken as an insult.
Often I marvel at how men love themselves more than others while at the same time caring more about what others think of them than what they think of themselves. (Marcus Aurelius, Meditations Book XII)
If you ever happen to turn your attention to externals, so as to wish to please anyone, be assured that you have ruined your scheme of life. Be contented, then, in everything with being a philosopher; and, if you wish to be thought so likewise by anyone, appear so to yourself, and it will suffice you. (Epictetus, Enchiridion 23)
Remember that you are an actor in a drama, of such a kind as the author pleases to make it. If short, of a short one; if long, of a long one. If it is his pleasure you should act a poor man, a cripple, a governor, or a private person, see that you act it naturally. For this is your business, to act well the character assigned you; to choose it is another's. (Epictetus, Endichirion 17)
The more you carry, the slower you go.
Is it not madness and the wildest lunacy to desire so much when you can hold so little? … [it is folly] to think that it is the amount of money and not the state of mind that matters! (Seneca, Consolation To Helvia)