From free samples to mass quantities of wholesale food, Costco is the perfect place to stock up on the essentials. Thus, it’s no surprise that Costco’s shoppers are extremely loyal, and while the grocery warehouse prioritizes its customer experiences, there's a good reason the stores don't offer express check-out lanes.

Simply put, Costco doesn't offer an express check-out option because the lanes probably wouldn't get enough use. According to Costco, most of its customers buy about 16 items every visit, and considering the average express check-out lane limits people to 15 items or less, an express lane Costco customer would be an anomaly.

However, the chain tries to streamline its check-out lanes with the motto, "no more than one member in line, and two members behind." To accomplish this, Costco spends millions to get its average checkout time down to about one minute, and the chain remains open to the possibility of a self-service check-out option.