"I'm sorry, but we are a little shorthanded today."

Why is that my problem?! Sure, if bubonic plague has swept through the office, or if the Russians dropped a bomb on the city, I can understand why you might have been taken by surprise. But people do get sick, and go on vacation, and have personal emergencies that come up, and any reasonable manager can foresee that; but if you do not staff your facility to deal with those FORSEEABLE situations, then you are planning to be shorthanded from time to time. But that is NOT MY PROBLEM!!!!! Hire enough people, and you would not be having to say that! If it is your strategic decision not to adequately staff your facility, that is your decision; but don't whine to me about why you cannot provide adequate service.