The aquarium shop where I work has been in business for more than 20 years. One Sunday a customer called wanting to buy a larger aquarium. "And by the way, I’ve spent a lot of money at your store over the years," he said. "I think I should get a discount."

"Only our owner can give a discount," I explained, "and he won’t be in until tomorrow."

When the customer said that he’d come in the next day, I asked him if there was anything else I could help him with.

"Sure," he said. "Where is your store located?"