Putting your shopping cart up on the curb/grass at Costco.
Look. I know about the shopping cart return litmus test for humanity. And in my experience, at the average supermarket or shopping center or whatever, it's usually not too bad. There are a couple of shit stains out there that leave their cart in a parking spot or anywhere else not returned.
But Costco? What the fuck is going on there? It's like the wild-fucking-west. It's lawless. I have seen people add to trains of carts stacked together in a parking spot. The curbs just have dozens of carts pushed up on them. It's like some kind of broken window theory parking lot where normally decent people see the state of it and go "No order exists here, and I will treat it as such"
Return your fucking cart. It takes like 40 seconds max.