We know, they didn't.
A local low-budget supermarket recently got their own self-check out stations, which I think is great; I like to use the self-checkout so I don't have to remove my headphones and talk to people. The down side is that many people in my area seem unaware of how to use one, causing massive delays, and to make matters worse, the supermarket manager thinks it's fine and dandy to not keep even 1 normal register open.
So while I understand some degree of confusion and annoyance, it still doesn't explain last night. It's close to closing so to cut the employees some slack, they were mostly busy with closing while one employee lingered near the registers, sweeping. I came in to quickly grab a pack of sugar and took the first available check-out counter.
One by one, several middle-aged (at least) men formed a line beside me. I look up and see that all 5 other self-checkout counters are completely free. I shrug and go back to scanning, ask the supermarket employee a question, then pay, grab my items and head out. Looking back as I scan my receipt to open the gate, the line of men were staring at me, without exaggeration, open-mouthed and aghast.
They appeared horrified and indignant that I had abandoned them, lingering in their self-inflicted queue, and I belatedly realized they were expecting me to check them out at the self-checkout register while the actual employee in the branded shirt hadn't been given so much as a second glance. Because the woman with the giant over-ear headphones and the Dark Brotherhood jacket is definitely here to help you pay for your pistachios, right?!