Anecdotes about David Hilbert:
From “Mathematical apocrypha redux: more stories and anecdotes of mathematicians”, by Steven George Krantz, p. 220:
Because she was a woman, the gifted mathematician Emmy Noether found her career derailed at every turn. Fortunately, the legendary David Hilbert allowed Noether to deliver lectures for courses listed under his name until, at last, she was appointed to a lectureship. When Hilbert's male colleagues objected to the presence of a woman in their midst, he gallantly rose to her defense again. "The faculty," he tartly remarked, "is not a bathing establishment."
Hilbert, famed for his absent-mindedness, attended a conference with Richard Courant at which several of the papers presented referred to this or that Hilbert Space. After one such presentation, Hilbert turned to Courant and asked a curious question: "Richard, exactly what is a Hilbert Space?"
David Hilbert (1862-1943)