I hate people who pull their cart through checkout, iin?
They've presumably been pushing it through the rest of the store like a normal person, but then at checkout they suddenly decide it would be a good idea to drag it behind them creating a roadblock. The worst part is they seem only vaguely aware they should keep control of their cart at all once their food is out of it. They will for example walk up a few feet to the card reader without moving their cart at all and then maybe 30 second later think "oh yeah, I guess I should move this out of the way"... then promptly forget about it again.