Another suggestion when you have a "Difficult Guest" who always seems to complain, is to hire them as a "Mystery Shopper". If you're picking up the cost of his meals anyway, you could make a good business deal and if you look very carefully at the reports, it may even help you to improve your operations. A conversation with the Guest might go like this:

"(Guest's name), I am frustrated because we cannot seem to meet your Expectations. You have great Expectations and my staff has difficulty meeting those standards."

"I believe that you are right most of the time and if we can provide for your needs, we will be a better Restaurant."

"What I would like to suggest is that you become a Mystery Shopper for me and evaluate our restaurant on a periodic basis. What this would entail is for you to come in like you normally would, evaluate the restaurant on our food and service. We would get together after and discuss your visit. I would pick up your meal expenses and we would discuss where you think we could improve our Service."

"It's important that you do not tell anyone about our arrangement so the evaluation can be the most effective. What do you think?"

This changes your relationship with the "Difficult Guest" from adversarial to constructive and chances are you will both benefit by making the difficult guest part of your restaurant marketing.

One final thing that you want to keep in mind is that when an employee makes a "mistake" it is a great opportunity to provide a level of service that this guest will never forget. Make it up to them, give them more than they would have received if everything went right. The goal is to have the guest "thank us for our solution to the problem and then to be so impressed that they will tell all their family and friends how great we are." This is Word of Mouth Advertising at its very best. Take advantage of it. Hopefully, the Guest will not only return themselves but will return and entertain their family and friends at your Restaurant. When this happens you know that your restaurant marketing is a success.