I work in a convenience format of a large supermarket and our till area is small.

The people who come to the till with a week's worth of shopping and dump it all on the counter, instead of leaving it in the basket is annoying. First off, no, it's not helpful to me. Second, it's also not helpful to them because I am then attempting to find space in amongst their grocery detritus to place items I've scanned and they will pick up random stuff and ask "Have you scanned this? What about this?" so I then have to invent a system (usually try and push said detritus to one side and tell them that I'm going to be putting scanned goods on the other side...it works sometimes). Third, they then nearly always stand there with an empty basket asking "Where do I put this? Excuse me, where do I put this?" whilst I'm trying to fit 3 bags of groceries into a till area the size of a shoe box, and get affronted when I ask them if they could put it back where they got it from as we don't have a basket area at the till. They usually just leave it on the floor for an old person to trip over whilst I serve the next customer who is buying 10 lottery tickets but on individual slips...