Never had anyone asking “Why are you working on Sunday?” (Universally Known And Accepted Answer In This Country: Penalty Rates), but I’ve often had people (especially at earlier jobs) asking why I’m working on public holidays (har har, yuk yuk), to which I’d fix them with an even smile and say “Because people like you insist on shopping on public holidays.”
I’ll have to use this in the future… 
Don’t forget, “You know, such and such store has that much cheaper!” “So go to such and such store!” (A friend of mine actually told someone that on his last day at his job)
I like it when the cashiers are pleasantly chatty–with one huge exception.
There is one older lady at my grocery store who always wants to chat when I’m in her line. She goes on about her family, my family, what I’m buying, what she’s cooking, whatever is on her mind. She ties every bag just so as she finishes it. If you tell her you need a bag of ice, she goes and gets it for you (as opposed to just letting me grab it on the way out.) She’s the slowest cashier in the store by a longshot.
Which would be fine…if they didn’t have her working in the store’s one express lane every afternoon. I usually drive past right when it gets busy in the late afternoon, and I usually stop by to grab one or two things. Her line is always six deep with poor souls with handbaskets who don’t realize they’d be far better off behind the two ladies with cartloads in the next lane.
Fortunately they just added self-scanners. Aside from the surprising number of people who seem astonished by this technology–odd, since the Wal-Mart two miles away has had this technology for most of a decade–this has smoothed out my afternoon considerably.
Yes. Mostly to the people ahead of me, whose item apparently has no bar code and is thus a great mystery to the hired help as to its value… It happens to me all the time, in a way. I buy, say, kumquats, and the clerk can’t find the code number for kumquats on the screen. I have to lean over and look at the list of fruits and search for it myself. There it is, I say, pointing. There, no there - #2019… IT’S #2019!.
I don’t mind a little chatting with cashiers. Sometimes they’re the only humans I talk with all day. I’m always amused at the young 'uns who look at, say, fennel or leeks, and ask me what it is and what am I going to do with it. 
But there’s one cashier who is so loquacious, who comments in a low, steady, non-stop stream on every single item she rings up. “Chocolate ice cream, oh, I love it, I like the chocolate fudge the best…apples? are you going to make a pie with this kind of apple?..candy bars? I’ll bet you want to hold onto these and eat one on the way home… soap? this has a pungent smell, I’ll put it in a separate bag…Four cases of soda, you must be having a big party…” Innocuous enough comments, but on EVERY ITEM? I avoid her checkout line at all costs. I’ll go stand in another line and wait 20 minutes longer to avoid her checkout line.