About a year ago, I went to the grocery store to buy coffee. They were out of the kind I usually get, so I chose another blend from the same company. Unfortunately, it tasted like crap, so I brought it back to the store. They refused to take it back, insisting that store policy prevents them from giving a refund on anything you’ve opened. I even asked one of the managers, who gave me the same story.

Prior to this little event, I shopped at that store a lot. I probably spent $200 a month there on groceries — until the coffee incident, anyway. Even though I was a loyal customer, they refused to make a small concession and take the bad coffee back. Instead, they clung to the sort of idiotic policies that really have no place in a small, locally-owned establishment.

I decided to shift my grocery spending to other retailers. Today, I’m buying most of my groceries at Trader Joe’s and Amazon. Trader Joe’s is a longer walk, but it’s also better food for less money. The point is that I would never have looked for alternatives if the local grocer just treated me right. In the year since the coffee incident, I’ve probably shifted $2,000 in spending to those other stores.

This means the local grocer has lost thousands of dollars in revenue and hundreds of dollars in margins over an $8 can of coffee. In all, this is a rather striking example of why you should treat your most loyal customers well, and never say that your official policies are set in stone.