Hilbert […] was perhaps the most absent-minded man who ever lived. He was a great friend of the physicist James Franck. One day when Hilbert was walking in the street he met James Franck and he said, “James, is your wife as mean as mine?” Well, Franck was taken aback by this statement and didn’t know quite what to say, and he said, “Well, what has your wife done?” And Hilbert said, “It was only this morning that I discovered quite by accident that my wife does not give me an egg for breakfast. Heaven knows how long this has been going on.”