How do you identify customers problem in a restaurant?

Ask them if they would like to see the manager. Always be polite, you want them to come back. If they are getting really shirty with you, pretend you don't speak very good english. If they want you to make them another replacement meal, carefully acess the scenario. If they wan't a really expensive meal, and there wasn't much wrong with the first one, apologise and explain that you can't. Be firm but fair. If its something little, then give them the replacement. You are not being a push over, you are coaxing them back to the restaraunt in the future. If they threaten you, stand your ground and keep calm. Get your boss, 2 against one will make them fallter, or politely ask them to leave the restaraunt. If they have made a mess and are apologising make a joke about it, then clean it up yourself. By law its not their responsibility. Always remain calm, polite and remember, the customer is always right. I hope my comment has helpt you. I'm off to listen to 'Strawberry Fields Forever' by The Beatles. It is a very soothing song, try singing it in your head if you're dealing with a tricky customer.