The soul of man does violence to itself...

The soul of man does violence to itself, first of all, when it becomes an abscess and, as it were, a tumour on the universe, so far as it can. For to be vexed at anything which happens is a separation of ourselves from nature, in some part of which the natures of all other things are contained. In the next place, the soul does violence to itself when it turns away from any man, or even moves towards him with the intention of injuring, such as are the souls of those who are angry. In the third place, the soul does violence to itself when it is overpowered by pleasure or by pain. Fourthly, when it plays a part, and does or says anything insincerely and untruly. Fifthly, when it allows any act of its own and any movement to be without an aim, and does anything thoughtlessly and without considering what it is, it being right that even the smallest things be done with reference to an end; and the end of rational animals is to follow the reason and the law of the most ancient city and polity.

Marcus Aurelius Antoninus Augustus, Meditations, Book II - 16.