There’s a bold and incredibly moving moment at the end of S07E07 (“Waterloo”) in Mad Men. Bert Cooper is dead. He died watching the moon landing; the last act of a man who belonged to the old world checking out just as the new one arrived. The next morning Don Draper is walking back to his office and Bert is there in argyle socks, no shoes, flanked by dancing secretaries, and he sings “The Best Things in Life Are Free.” It’s one of the strangest things the show ever did. Mad Men was built on ...