'Above all, don't lie to yourself' - Fyodor Dostoevsky's The Brothers Karamazov

Above all, don't lie to yourself. The man who lies to himself and listens to his own lie comes to such a pass that he cannot distinguish the truth within him, or around him, and so loses all respect for himself and for others. And having no respect he ceases to love, and in order to occupy and distract himself without love he gives way to passions and coarse pleasures, and sinks to bestiality in his vices, all from continual lying to other men and to himself.

And above all, do not be so ashamed of yourself, for that is at the root of it all … You have known for a long time what you must do. You have sense enough: don't give way to drunkenness and incontinence of speech; don't give way to sensual lust; and, above all, to the love of money. And close your taverns. If you can't close all, at least two or three. And, above all—don't lie … Above all, don't lie to yourself. The man who lies to himself and listens to his own lie comes to such a pass that he cannot distinguish the truth within him, or around him, and so loses all respect for himself and for others. And having no respect he ceases to love, and in order to occupy and distract himself without love he gives way to passions and coarse pleasures, and sinks to bestiality in his vices, all from continual lying to other men and to himself. The man who lies to himself can be more easily offended than any one. You know it is sometimes very pleasant to take offense, isn't it? A man may know that nobody has insulted him, but that he has invented the insult for himself, has lied and exaggerated to make it picturesque, has caught at a word and made a mountain out of a molehill—he knows that himself, yet he will be the first to take offense, and will revel in his resentment till he feels great pleasure in it, and so pass to genuine vindictiveness. But get up, sit down, I beg you. All this, too, is deceitful posturing …