In Germany, supermarket workers are always very nice, because they have to. The cashiers have to ask every single customer:
"How was your shopping?" or "Was everything ok with your shopping?", if they don't, and the boss sees it, they get fired. At least it's like that in the biggest supermarket in my town, it isn't that harsh in the little shops.
Of course like 99% of all customers just say "Yes" or "Yes, everything fine". One day, when my mother was really stressed from work and didn't find what she searched for (it was out of stock or they had rearranged some goods in the market) she answered something along:
"No nothing is fine, it's a shit day, and I didn't even find everything I needed in the market, because you always rearrange things every few weeks instead of let everything be in it's place!"
And the till girl was like "Wut the fuck, y u tell me that, it's not my fault?! "
Of course my mother wasn't really serious, and of course she knew if anyone in the market has no fault for things like that, then it's the till girls.
At home she told me that the facial expression of the till girl was priceless.
Fuck dis society, fuck da police, fuck dis system! 
Really? everytime you go in a supermarkets the cashiers ask you if your shopping was ok and stuff like that?
In the supermarkets here the cashiers just say "good morning/afternoon/evening", put the stuff you want to buy on the barcode reader, give you a/some bag/s if you ask ( or they ask if u need some), tell you how much you have to pay, give you the receipt then they say "bye or bye thank you" and that's it.
So do they ask question like "how was your shopping" because it's a policy of the supermarket and the manager gets upset if they don't?
That's a weird policy imo, personally I expect the cashiers to do their job and be quick, it would annoy me if they ask useless questions like "how was your shopping".
However in restaurants here when you pay the bill they often ask you "was everything ok" and stuff like that, but they could avoid that, unless they want to offer a digestive like a shot of grappa/schnapps, or something like that
.
It's like when someone asks you (at least in Germany): "How are you?" Nobody expects to hear the thruth or something bad, everybody just expects you to say "Yes, I'm fine".
Yes, i guess it's the same everywhere, it's a shit question imo when it's asked by someone who is just an acquaintance.
