F.A. Hayek in Notes on Liberty:
I believe it was on the last day of August 1918 that here, among a boisterous crowd of young officers returning to the front after visiting their families on furlough in the Salzkammergut district, two artillery ensigns became vaguely aware that they ought to know one another. I am not sure whether it was a resemblance to other members of our families or because we had actually met before that led us to ask the other, “Aren’t you a Wittgenstein?” (or, perhaps, “Aren’t you a Hayek?”). At any rate it led to our travelling together through the night to Vienna, and even though most of the time we naturally tried to sleep we did manage to converse a little.
Some parts of this conversation made a strong impression on me. He was not only much irritated by the high spirits of the noisy and probably half-drunk party of fellow-officers with which we shared the carriage without in the least concealing his contempt for mankind in general, but he also took it for granted that any relation of his no matter how distantly connected must have the same standards as himself. He was not so very wrong! I was then very young and inexperienced, barely nineteen and the product of what would now be called a puritanical education: the kind in which the ice-cold bath my father took every morning was the much admired (though rarely imitated) standard of discipline for body and mind. And Ludwig Wittgenstein was just ten years my senior.
What struck me most in this conversation was a radical passion for truthfulness in everything (which I came to know as a characteristic vogue among the young Viennese intellectuals of the generation immediately preceding mine only in the following university years). This truthfulness became almost a fashion in that border group between the purely Jewish and the purely Gentile parts of the intelligentsia in which I came so much to move. It meant much more than truth in speech. One had to “live” truth and not tolerate any pretence in oneself or others. It sometimes produced outright rudeness and, certainly, unpleasantness.
More here.