Leaving your cart in an empty self-check aisle and then going to fetch however many more things is not okay. There is no "saving" a spot at the grocery store honey. Especially when you don't mention it to anyone nearby. Everyone was rolling their eyes at you.
The Cranky Semi-Old who moved your cart to use the damn lane myself. Weirdly everyone else was just standing there waiting for another register to free up. You're doing it wrong people!