Book VII · 69
The perfection of moral character consists in this, in passing every day as the last, and in being neither violently excited nor torpid nor playing the hypocrite.
This is the mark of a perfect character, to pass through each day as if it were the last, without agitation, without torpor, without pretence.
Marcus Aurelius, Meditations VII.69. Translated by George Long (1862). The Stoic Library.