This is probably about you, so please pay attention.
Your typical grocery store aisle is fairly narrow -- just barely wide enough for two carts to pass each other. At any given time, you probably are not the only person in the grocery store. This means that when you leave your cart sitting directly in the middle of an aisle while you wander aimlessly away, you are grossly inconveniencing your fellow shoppers. Knock it off. It doesn’t take any additional effort to leave your cart six inches to the right.
Now, maybe you’re a reasonably good and thoughtful person, and you don’t do that. You leave your cart all the way to one side of the aisle. Good for you! You’re ready for lesson number two. You know those mid-aisle displays the grocery store puts up to try to get you to buy Ritz Crackers or whatever? Well, those are not holograms; they are tangible objects. Carts have to go around them. This means that when you stop your cart right next to one of those displays, you are blocking off the entire aisle, grossly inconveniencing your fellow shoppers. Knock it off. Leave your cart in-line with the display, on the same side of the aisle. It really isn’t difficult.
Look, grocery stores are crowded, cluttered places with often illogical layouts, and three-quarters of the city trying to get their shopping done at the same time. They’re generally a pain in the ass, and nobody wants to be there any longer than necessary. Don’t make it worse than it needs to be. We’re all in this together. Behave. Or I’ll slip a container of caviar in your cart when you aren’t looking.