Guinness is an inseparable part of the modern St. Patrick's Day tradition. Picture Post/Hulton Archive/Getty ImagesAs you might expect, St. Patrick's Day is a huge deal in his old stomping grounds. (The one exception went to beer vendors at the big national dog show, which was always held on St. Patrick's Day.) In 2017, it was estimated that 13 million pints of Guinness would be consumed worldwide on St. Patrick's Day. You can't attend a St. Patrick’s Day event without hearing a cry of \"Erin go Bragh.\"