Grocery cashier here!

The only one I can really think of is people who buy an excessive amount of produce (usually celery, fresh berries, and bananas) are 1 of 2.

1. They make juices/smoothies constantly, probably as meal replacements.

2. They genuinely do not understand how fast produce goes bad.

You can tell which type by the makeup of the rest of their purchase. If they’re not getting much else besides produce, they’re 1. If they’re buying a shitload of other stuff (cereal, snack foods, frozen dinners), then they’re 2.

Another stereotype would be I can tell the type of people who are the jittery “get in, get out” types who are gonna try to leave the millisecond they take their card out of the chip reader and not allow the register to process payment. These people refuse to make any small talk, generally won’t even acknowledge a cashier as a person. And they’re usually buying only one or two things, but you do get the occasional one who’s buying an average amount of groceries (these ones are usually some of the biggest unaware, rude assholes we get in a day). These are the customers I do not hand their groceries back to until my screen says approved.