I swear that self checkout is invisible to customers

So I work in a small convenience store, but it often gets busy, as it’s right next to metro station and multiple bus and tram stops.

There’s one regular cash register and one self checkout. Because there’s only two people during shift (unless my boss comes in to help), I often have to leave the register to help out with unpacking deliveries, stocking shelves, cleaning the store etc. When I leave the register, I put up a large sign that says if you’re paying with card to use the self checkout.

But customers ignore it. Today it took me half my shift to even refill the coffee machine (pour milk and beans and restock the paper cups), because every time I left the register, someone would come in, stand in front of it and signal me to come back.

Half the times those were people paying with card, not needing any of my assistance (with handing something from behind the register, preparing the food or weighing fruits). Multiple times I got told off that I’m too slow and that they’re going to miss their train/bus/whatever. What’s so hard about going to the self checkout if you’re paying with card for just one bottle of water? It’s way faster to use the self checkout than to wait for me to drop what I’m doing, come back, go through my script (asking for app and recommending a candy bar, it’s something that I’d get in big trouble for not doing if caught by the “mystery shoppers” send by corporate) etc.

Then my shift ends. There’s a huge line taking up most of the store. My coworker can’t really help, because there’s only one register, I can’t leave until I count the cash in the till. I yell out that anyone not paying with cash should use the self checkout. Nobody even reacts. Then half the people proceed to pay with card and act annoyed that the wait is so long and I end up leaving 15 minutes later than I was supposed to (there’s no paid overtime).

I don’t get it, what’s the problem? Is it invisible? Is this some kind of pride thing, that they don’t want to do “my job” of scanning the items? It wastes so much of my time and their time every single shift and I really don’t get what the problem is.