ran an opinion piece recently that argued that self-checkout at the grocery was a failure. I can't argue with some of the author's complaints; for example, it takes somewhat longer because I have to look up some of the fresh produce codes that the experienced checkers know by heart. But I'm going to take strong exception to one of the advantages credited to human checkers, and that's the human checker packing the bags. Or more likely where I live, a dedicated teenager doing that job.
I have high standards for packing bags. One bag, usually, since I have a bloody great reusable canvas bag that I carry for the purpose. I learned bag packing by watching a master. When I was a graduate student in Texas, I rode my bike to campus almost every day and stopped at the little neighborhood grocery for whatever was on my list every couple of days. The old lady that checked me out and packed my bag always got everything in a paper bag with handles that I could hold with one hand while I gripped the handlebars. Every item, every time, one bag, nothing crushed. On rare occasions she would take some things out and repack them, but not often. She was amazing. I was studying applied math at the time and was always tempted to tell her, "But don't you know that the knapsack problem is supposed to be hard?"
I'm familiar with the dimensions of my bag. Before I start packing I look at the stuff and make a plan based on their shapes . I can put a relatively large amount of stuff in it -- far more than the teenaged bag-packers ever seem able to manage. It's sturdy and I'm still relatively fit, so I don't mind that it weighs 25 pounds some days. The kids are even worse about the plastic film bags that they put the overflow in. I got frustrated enough one day that I emptied the bags they had packed for me -- my canvas bag plus three plastics -- and put it all in the canvas bag.
I go through the self-check lines because I get to pack my own bag. It's a feature, not a bug.
 There are a few exceptions that don't go in the bag. If I have an eight-pack of paper towels, I carry it separately in my other hand, as it would pretty much fill the bag by itself.
Photo credit: Bloomberg News