Professor Leonard Schlesinger of the Harvard Business School, considered one of America’s foremost experts on customer service, had one of his greatest moments of insight while waiting in a grocery checkout line. As he waited with his full basket, he watched customers breezing through the express line. He wondered, “Why is the store punishing me, making me wait for a long time with my $300 cart, while people spending $3 get the royal treatment?” It seemed the store wasn’t analyzing customer data and didn’t know their customers. To Schlesinger, the issue had to do with a misalignment of customer service and customer prioritization. The supermarket couldn’t identify its best customers.