Sextius had this habit, and when the day was over and he had retired to his nightly rest, he would put these questions to his soul: ‘What bad habit have you cured today? What fault have you resisted? In what respect are you better?’ Anger will cease and become more controllable if it finds that it must appear before a judge every day. Can anything be more excellent than this practice of thoroughly sifting the whole day? And how delightful the sleep that follows this self-examination – how tranquil it is, how deep and untroubled, when the soul has either praised or admonished itself, and when this secret examiner and critic of self has given report of its own character! I avail myself of this privilege, and every day I plead my cause before the bar of self. When the light has been removed from sight, and my wife, long aware of my habit, has become silent, I scan the whole of my day and retrace all my deeds and words. I conceal nothing from myself, I omit nothing. For why should I shrink from any of my mistakes, when I may commune thus with myself?
‘See that you never do that again; I will pardon you this time. In that dispute, you spoke too offensively; after this don’t have encounters with ignorant people; those who have never learned do not want to learn. You reproved that man more frankly than you ought, and consequently you have not so much mended him as offended him. In the future, consider not only the truth of what you say, but also whether the man to whom you are speaking can endure the truth. A good man accepts reproof gladly; the worse a man is the more bitterly he resents it.’
Seneca, On Anger, 3.36.1-4