If you don’t wear green on St. Patrick’s Day, prepare to be pinched. But only if you’re in the U.S. This is an American tradition that is traced to the 1700s. An old Irish legend has it that those who wear green are invisible to leprechauns, those fairy creatures who randomly pinch people no matter what color they’re wearing. So folks started pinching anyone who didn’t wear green as a reminder of the leprechauns and their sneaky ways.