The battle of the burgers is on. But at the center, there’s no actual fast food. Instead, it features viral moments of the companies’ leaders. In case you missed it: Last weekend, an Instagram video of McDonald’s CEO and chairman Chris Kempczinski—looking rather uncomfortable as he sampled his own company’s newly launched Big Arch burger—was widely circulated and mocked across the internet. He took only one small bite and repeatedly called the food a “product.” “I love this product,”...