Say to them "I apologize, Sir/Ma'am." Then, you help them or get someone to help them with the problem they're having. Also one way is to give the customer the reason and look at his or her eyes...
First, make sure the police or security is near by. Next, treat the customer normally. If anything happens, the police or security will handle everything from there.
First, ask them to politely tell you what the problem is. Then tell them you are willing to listen and try to find a solution to their problem. If they continue to be irrate in an abusive way, let...