evidence: The Apocryphal Twain: "The things you didn’t do." [...] David Sivak of CheckYourFact.com did a story on this ubiquitous piece of Twain apocrypha this week and contacted me for comment, so I figured it was a good time to add it to our own archive. David rightly deduced that this is not something Mark Twain said. The more interesting part of these columns, as far as I’m concerned, is who did the quote actually come from and how did it come to be associated with Twain. Unlike many of the apocryphal aphorism I have trace over the past couple years, this false attribution traces back to before the social media era. Because of that endurance, the attribution seems more credible. Books and periodicals produced by reputable publishers and institution – including, for instance, the US Navy – attributed the quote to Twain before the turn of the 21st century. [...] A couple years earlier, Harry Haun had published his Movie Quote Book, in which he reported that on the set of Mildred Pierce (1945), 31-year-old Zachary Scott told 41-year-old Joan Crawford, "As you grow older, you’ll find the the only things you regret are the things you didn’t do."