“I recall once saying that when I had given the same lecture several times I couldn't help feeling that they really ought to know it by now.”
"Academic Life", p. 135.
Littlewood's Miscellany (1986)
Help us to complete the source, original and additional information
John Edensor Littlewood 6
English Mathematician 1885–1977Related quotes

“It's life's illusions that I recall, I really don't know life at all”

1860s
Context: In this sad world of ours, sorrow comes to all; and, to the young, it comes with bitterest agony, because it takes them unawares. The older have learned to ever expect it. I am anxious to afford some alleviation of your present distress. Perfect relief is not possible, except with time. You can not now realize that you will ever feel better. Is not this so? And yet it is a mistake. You are sure to be happy again. To know this, which is certainly true, will make you some less miserable now. I have had experience enough to know what I say; and you need only to believe it, to feel better at once.
Letter to Fanny McCullough (23 December 1862); Collected Works of Abraham Lincoln, edited by Roy P. Basler

This Business of Living (1935-1950)

So Nasreddin said Let the half who know what I am going to say, tell it to the half who don't, and left.
Alice Kelsey, Once the Hodja (1943), ISBN 0679251014

http://www.flixster.com/actor/leonardo-di-caprio/leonardo-dicaprio-quotes

Marek Sanak, geneticist and molecular biologist, friend and disciple of Vetulani. Kobos, Andrzej (2012). Po drogach uczonych. 5. Polska Akademia Umiejętności. p. 334. ISBN 978-83-7676-127-5.