What are the joys and miseries of singlehood? Is “playing hard to get” an effective dating strategy? Why does it feel so good to be adored “just as we are”? Paul and Eli revisit “Bridget Jones’s Diary,” the 2001 rom-com starring Renee Zellweger, Hugh Grant, and Colin Firth—which Vanity Fair recently ranked as the fourth best romantic comedy of all time.