At a diner, I was standing in line to pay my bill behind two women who handed the young waitress a credit card.

After swiping the card, she loudly called out to her manager, "Mr. Allen, what do I do if it says 'reject'?"

As the women's faces reddened and customers turned to look, Mr. Allen, also the cook, calmly walked out from the kitchen.

"Well," he answered, "the first thing you do is shout it out loud enough to embarrass the customer, who might have been thinking about leaving you a tip."