Is This the 1 Secret to Costco's Success?

To say that Costco (COST -0.35%) has worked out to be a wonderful investment would be pretty accurate. Including dividends, if you invested $10,000 in the business five years ago, you'd be sitting on more than$35,000 today. This meaningfully outpaces the Nasdaq Composite Index. Of course, credit goes to strong fundamental performance. But there's another factor investors might not be aware of. Is this the one secret to Costco's success?Keep the customers coming backCostco isn't unlike any other general mer ...