Sed nihil prodest privatae tristitiae causas abiecisse; occupat enim nonnumquam odium generis humani. cum cogitaveris, quam sit rara simplicitas et quam ignota innocentia et vix umquam, nisi eum expedit, fides, et occurrit tot scelerum felicium turba et libidinis lucra damnaque pariter invisa et ambitio usque eo iam se suis non continens terminis, ut per turpitudinem splendeat: agitur animus in noctem et velut eversis virtutibus, quas nec sperare licet nec habere prodest, tenebrae oboriuntur. in hoc itaque flectendi sumus, ut omnia vulgi vitia non invisa nobis sed ridicula videantur et Democritum potius imitemur quam Heraclitum. hic enim, quotiens in publicum processerat, flebat, ille ridebat; huic omnia quae agimus miseriae, illi ineptiae videbantur. elevanda ergo omnia et facili animo ferenda; humanius est deridere vitam quam deplorare.
(Seneca Minor, De Tranquillitate Animi 15.1-2)
But it is useless to cast away the reasons for private sadness; for sometimes loathing for the human race takes possession of us. When you think how rare honesty is and how unknown is innocence, and good faith is scarcely maintained at all unless it is in men’s interest, and such a crowd of successful crimes confronts us, along with the profits and losses of lust, both equally hateful—not to mention ambition so unable to keep within its limits that its shamefulness is glaring—the mind is driven into night, and the darkness rises up as if the virtues had been overthrown, since one cannot hope for them and gains nothing from possessing them. Therefore we must bend so as to make all the vices of the crowd seem not hateful but absurd, and imitate Democritus rather than Heraclitus. For whenever Heraclitus went into public places he wept, whereas Democritus laughed: to Heraclitus all our activities seemed wretched, to Democritus sheer folly. So we must mitigate everything and bear it with an easy mind; it is more humane to make fun of life than to bewail it. (tr. Elaine Fantham)
Crambe Repetita 