Anyone who's ever worked in the restaurant industry knows it isn't easy. Each day brings a new set of challenging tasks and you're constantly dealing with difficult customers.For one restaurant in Middlesbrough, England, a regular Friday night, became anything but ordinary. When it came time to pay the bill, three friends disappeared without closing the tab. But that wasn't the oddest part—a few days later, the owner of the restaurant received an unexpected letter from the customers. So, why did the friends dine and dash, and what was so special about the letter?