“All the proliferating falsifications of what I and everyone I know experienced once in what it is now so convenient to call the "fifties" or "sixties," as if life was really measured or lived in arbitrary decades, when the history books are sold like comix.”

Source: Will Grayson, Will Grayson

Source: 1963 - 1967, What Is Pop Art? Interviews with Eight Painters, Part 1 (1963), pp. 116-19

My Own Epitaph, inscribed on Gay’s monument in Westminster Abbey; also quoted as "I thought so once; but now I know it".
Variant: Life is a jest, and all things show it,
I thought so once, and now I know it.

Source: The Unabridged Journals of Sylvia Plath

Context: I do not say that I do not know whether this faith is true, or not. I say distinctly and clearly, that I know it is not true. I admit that I do not know whether there is any infinite personality or not, because I do not know that my mind is an absolute standard. But according to my mind, there is no such personality; and according to my mind, it is an infinite absurdity to suppose that there is such an infinite personality. But I do know something of human nature; I do know a little of the history of mankind; and I know enough to know that what is known as the Christian faith, is not true. I am perfectly satisfied, beyond all doubt and beyond all per-adventure, that all miracles are falsehoods. I know as well as I know that I live—that others live—that what you call your faith, is not true.

… Well that's very much true. I find a lot in common in the way I manage things and the way she manages three-year olds. We humans are the same when we are three years old and when we are 50!
Comparing his work as an international diplomat to that of his wife, Aida Elkachef, a kindergarten teacher, with a mention of the book by Robert Fulghum.
Breaking the Cycle (2003)

Introduction: The Misjudgment of Paris
The Burden of Responsibility: Blum, Camus, Aron, and the French Twentieth Century (1998)

RTNDA Convention Speech (1958)