Customers are funny people. Many of them are loyal, even if they have a problem. But almost all of them hate the next two words I'm about to toss out.
"Sorry" and "But" are the two words.
Customers hate these two words because they both signal disappointment and lack of accountability. Saying "sorry" means something went wrong and you can't or are unwilling to fix the issue. Saying "but" usually is a way to sneak an alternative offer or change the subject. Customers hate these words.
"Sorry, we don't have any more ham sandwiches. Did you want a turkey sandwich?" -Um, most people ordering a ham sandwich don't want turkey. Sorry only means you're not willing to take responsibility for the issue- even if you're the waitress delivering the message. A better way to handle this situation is as follows;
"We are out of ham for the day. We have everything else noted on the menu. Did you want to review other choices and I can come back in a few minutes?" While you're still saying there is no ham, you're giving the customer power over the situation. He doesn't have to accept turkey and he can chose his second favorite item. You're also not apologizing for something out of your control and that you can't do anything about.
"It is going to cost you a thousand dollars to fix your breaks, but the resale value will improve." - The but in this sentence doesn't need to be added. The cost of the item is what it is. If you can't justify the use of breaks to a customer, he isn't worried about resale value!
So, most of the time customers aren't upset by mistakes or disappointments. They are, however, more agitated by the way things are presented to them. Leave out the words "sorry" and "but" and you will have happier customers.