I've gone to a supermarket before. In fact when I was young I was forced by the system to work as a cashier at one, and to this day, a decade and a half later, I can't think of a worse feeling than sitting 8 hours a day doing absolutely nothing. It was a small town, so there weren't many customers, and all I could think while I looked at the shelves full of useless products was that I'd much rather be doing anything even slightly intellectual stimulating. This was around the time when I started getting into programming, so you can imagine how miserable I was that I couldn't spend that time learning / producing.

It's easy to see this from the perspective of the customer only, but think of how many lives and brilliant minds are being wasted away in the system.