Or so I have to assume.
I just got back from a shopping trip to Costco. The store was packed, probably with people shopping early to avoid the heat (predicted high of 100 degrees or more today), and as usual, I was astonished at how many people do things with their shopping carts that they wouldn't do in their cars. Driving on the wrong side of the aisle. Leaving their carts across the middle of the traffic flow while they wander off to find something on the shelves. Stopping to chat or eat free samples, with their carts sticking out into the flow.
To be fair, it's not just Costco. I see the same thing in the regular supermarket, where I'll be going in a couple of hours. Interestingly, it's almost always women who do these things. Male shoppers seem to drive their carts much more rationally. I expect some disagreement with that statement.
Maybe it's not the carts that do that to people. You do see the equivalent strange behavior when people are driving cars, so maybe the dangerous cart drivers I'm complaining about are actually the same people I have to watch out for while driving my car in Denver.