> Sunday, 29 June 1975, has gone down in computing history as the day on which Steve Wozniak first showed Steve Jobs a working prototype of the Apple 1, and as the first time that someone typed a character on the keyboard of a personal computer and it appeared on a screen. ... Said Wozniak, “You know I’m a prankster — I actually made up that date and just kept repeating it.” The actual event, as he can best recall, happened weeks or months later.

I don't get it. How is citing a decades-old date weeks before the real date a "prank"?