Little pieces of wisdom from Les Liaisons Dangereuses, by Choderlos de Laclos

On passion and prudence:

"What you call happiness is but a tumult of the senses, a tempest of passions of which the mere view from the shore is terrible. Ah! Why confront these tempests? How dare embark upon a sea covered with the debris of so many thousand shipwrecks?" -- Madame de Tourvel

"I say my principles, and I say so decidedly; for they are not, like those of other women, the result of chance, received without scrutiny, and followed out of habit; they are the fruit of my profound reflections; I have created them, and I may say that I am my own handiwork." -- Marquise de Merteuil.

"What would virtue be without the duties which it imposes? Its worship lies in our sacrifices, its recompense in our hearts. These truths cannot be denied except by those who have an interest in disregarding them, and who, already depraved, hope to have a moment's illusion by endeavoring to justify their bad conduct by bad reasons." -- Marquise de Merteuil.

"It is not for the illusion of a moment to settle the choice of our life. In fact, in order to choose, one must compare; and how can that be done, when one is occupied by a single object, when even that object one cannot know, plunged as one is in intoxication and blindness?" -- Marquise de Merteuil.

"To what lengths will vanity not carry us! The wise man was right, indeed, when he said that it was the enemy of happiness." -- Marquise de Merteuil.

"Who is there who would not shudder, if he were to reflect upon the misfortunes that may be caused by even one dangerous acquaintance! And what troubles would one not avert by reflecting on this more often!" -- Madame de Volanges