A thought popped into Stephen Bonser’s head midway through Valentine’s Day. “If I went to Outback Steakhouse by myself tonight and asked for a table for 2, then got progressively sadder as the night went on alone, do you think they’d give me my steak for free?” the 27-year-old, who works in technology sales and lives in Washington, asked his hundreds of Twitter followers. His sister egged him on, telling him that she would pay for his meal on Thursday if the restaurant didn’t. Three hours later, Bonser was waiting by the host stand at the Outback Steakhouse in Arlington,...