For more than two decades, Alicia Grandey, a professor of psychology at Penn State, has been studying how the mistreatment of frontline service workers affects their health and productivity. The behavior she examines ranges from verbal abuse to racial or sexual harassment. She also looks at ambiguous circumstances, in which it’s unclear whether any harm was meant, such as when a customer doesn’t hold the door for an employee walking behind them. With reports of incivility on the front lines of business . . .