“His courtesy was somewhat extravagant. He would write and thank people who wrote to thank him for wedding presents and when he encountered anyone as punctilious as himself the correspondence ended only with death.”

Variant translations:
Above all, do not lie to yourself. A man who lies to himself and listens to his own lie comes to a point where he does not discern any truth either in himself or anywhere around him, and thus falls into disrespect towards himself and others. Not respecting anyone, he ceases to love, and having no love, he gives himself up to passions and coarse pleasures, in order to occupy and amuse himself, and in his vices reaches complete bestiality, and it all comes from lying continually to others and to himself. A man who lies to himself is often the first to take offense. It sometimes feels very good to take offense, doesn't it? And surely he knows that no one has offended him, and that he himself has invented the offense and told lies just for the beauty of it, that he has exaggerated for the sake of effect, that he has picked on a word and made a mountain out of a pea — he knows all of that, and still he is the first to take offense, he likes feeling offended, it gives him great pleasure, and thus he reaches the point of real hostility… Do get up from your knees and sit down, I beg you, these posturings are false, too.
Part I, Book I: A Nice Little Family, Ch. 2 : The Old Buffoon; as translated by Richard Pevear and Larissa Volokhonsky, p. 44
The Brothers Karamazov (1879–1880)

trans. Michael Chase (1995), p. 91
La Philosophie comme manière de vivre (2001)
Context: Only he who is capable of a genuine encounter with the other is capable of an authentic encounter with himself, and the converse is equally true…From this perspective, every spiritual exercise is a dialogue, insofar as it is an exercise of authentic presence, to oneself and to others.

Variant: But then anyone who's worth anything reads just what he likes, as the mood takes him, and with extravagant enthusiasm.
Source: Jacob's Room

Page 46.
Golden Booklet of the True Christian Life (1551)

1777
Bartlett's Familiar Quotations, 10th ed. (1919), Life of Johnson (Boswell)

Salt from My Attic (1928), The Mosher Press, Portland, Maine; cited in The Yale Book of Quotations (2006) ed. Fred R. Shapiro, p. 705; there are numerous variants of this expression.