As winter gives way to spring, a number of holiday and other family events—be it Passover, graduation, first communion, you name it—stand before us. And, with them, comes a certain degree of anxiety for most of us, knowing that it means spending some “quality time” with our extended family. No matter how much we may love them, bringing all those personalities together is an inevitable recipe for tension. That’s why we can all use a coach like etiquette expert, Marie Dubuque—an unparalleled guru in interpersonal relationships and a wellspring of common-sensibility advice for all of us humans who can’t help...