That's what I was getting at. Thanks for summing it up. And don't waste time having to deal with a drink besides so you either have to set it somewhere where it might be spilled or else you have to deal with everything with only one available hand.
It's possible there weren't other check-outs open at that time of night. Of course I don't know for sure. But that could explain why someone couldn't move to another check-out line, which would be frustrating for those waiting. Not that anyone should be assaulted over it.
We don't use a lot of coupons but when we do, we pull each one from the bunch as we put the items in our cart, so they're ready to hand to the checker when we go through the line. It would be way too confusing and time-consuming to be sorting through coupons at the check-out. We also have our CC ready to swipe when the order is totaled, so we're not fumbling around looking for a way to pay and acting like it's a surprise we actually are expected to give them money, and holding up the line while we look. When we wrote checks, we always had them filled out as much as possible before the bill was totaled. It doesn't take much thought to be more considerate of other people waiting in line.
We getting to be really big fans of WM's self-checkout option.

Usually no lines to wait in, no surly checkers getting annoyed with us for using our own bags, nobody waiting in line behind us, just ourselves and we can take our time, plus they have a person right there watching all the self-check places so if there's an issue, it can be immediately dealt with. We've used those in several stores and the people we've dealt with in each store were always patient and polite.