Francois de La Rochefoucauld

François VI, Duc de La Rochefoucauld, Prince de Marcillac (15 September 1613 – 17 March 1680) an accomplished French moralist of the era of French Classical literature and author of Maximes and Memoirs, the only two works of his dense literary œuvre published. His Maximes portray the callous nature of human conduct, with a cynical attitude towards putative virtue and avowals of affection, friendship, love, and loyalty. 

We lie to other people so often that we get used to it, and we start to lie to ourselves.