How much would you pay for an egg? Fifty cents? Two dollars? How about $6,000?

That's how much it cost one restaurant in Newport Beach, Calif., which refused to honor a customer's request. The money wasn't lost through legal action or any formal process. Rather, it represents the lost business that eatery suffered - because of one egg.

Let me explain. Authors Deb and Todd Duncan, whose careers also include television production and peak performance training, detail the 10 new golden rules of customer service in their new book, "The $6,000 Egg."

Deb and Todd were frequent patrons at a chic test kitchen that experiments with new menu items. One day, the featured special was a waffle served with an egg on top. The couple wanted a cheeseburger, which was on the menu, but asked to have a fried egg added on top of the burger. They were surprised to hear from the server that the kitchen might not be able to do that. Sure enough, even though they were making eggs for the waffles, the server told them the kitchen was too busy to make one for the burger. So they asked a different server who knew them well.

The answer was still no, because it wasn't on the menu.

When they asked to speak to the manager, she approached without a smile. After yet another request, she stood firm, explaining the restaurant only orders a certain number of eggs per day, and they couldn't sacrifice one for a cheeseburger.

Todd was incredulous. He asked her, "So a one-time visitor who orders a waffle for $15 is more important to you than a $6,000 customer who comes in at least four to six times a month?"

Her response was a textbook lesson in terrible customer service. "If we run out of eggs, we can't serve the waffle." So when Todd suggested she might be able to send a busser down the block to buy a few extra eggs, she offered to cover their check for their inconvenience.

He couldn't believe she would rather pay their $75 tab than sell them a single egg. They left, and vowed never to return.

They wound up at a restaurant next door, where they shared their experience. There, the server told them that their company creed is "We don't say no here." And they don't need the manager's permission to satisfy customer requests.

Guess where they go for breakfast now.

So many of the rules the Duncans include in their book are simply common sense, yet they are broken over and over again.

Perhaps the most frequent complaint I hear from readers is that they are repeatedly disappointed in the service they receive, even from companies they have done business with for years. Those companies would be wise to remember that one bad experience can destroy customer loyalty. And anyone in business knows it is much more expensive to find new customers than to retain existing ones.

Our motto at MackayMitchell Envelope Co. is: "To be in business forever." That's getting to be a tall order, since technology has replaced the need for envelopes in many instances.

Remember, most customers aren't asking for miracles. They might have special requests or needs that are not part of your usual offerings. But if you can accommodate them, do it. Don't make your customers walk on eggshells.

Mackay's Moral: Great customer service is the goose that lays the golden egg.

Harvey Mackay is the author of the New York Times best-seller "Swim With the Sharks Without Being Eaten Alive." He can be reached through his website, www.harveymackay.com, by emailing harvey@mackay.com or by writing him at MackayMitchell Envelope Co., 2100 Elm St. SE, Minneapolis, MN 55414.