I work in retail and we are instructed to make conversation, and if a mystery shopper comes in and we don't follow the script, say hello, would they like bags, do they need a hand packing, make chit chat (usually about the weather or things on the checkout conveyor), give them their total, giving change and wishing them a good day all with a smile then we get marked down and a rollocking off the manager ... but then we get attitude off customers when we are doing just that and no choice but to do it. Also, sometimes, 8 hours into a 10 hour shift, I just want a little social interaction that isn't one of those questions, maybe I have been meaning to try that new yoghurt brand I've just scanned through for you and when I ask your opinion of it I genuinely want to know. Or when I scan a clothes item through, when I say I was looking at it earlier, and trying to resist buying it, even if it is in the sale I am being genuine about it because I am praying that there will still be one left in my size at the end of my shift.
People like to think that when they don't want to chat they are polite about it, but not everyone is. I have had customers hold up their hand and say "Don't talk to me" as soon as I've said "Good morning,". I've had queueing customers kick off at me because a customer changed their mind about an expensive item which required a supervisor key to void off and they've had to wait, despite the fact I hate it as much as they do. I've had customers entirely ignore me, even going as far as to drop their money on the checkout rather than put it in my hand - but if I did the same then they'd report me for being rude. I've had (perfectly able) customers accept help to pack their shopping and then stood back and done nothing but criticise my packing as I packed their months worth of shopping. Working on the self scan machines I've had people whistle at me, click their fingers, grab me as I'm walking past, swear at me for not being quick enough getting to them when I've had three other issues to deal with, call me a jobsworth for reminding them that they haven't paid for the 6 carrier bags they've tried to walk out with, have a tantrum because the macjine they used was cash only "but it isn't clear" despite it saying on the sign, on the screen, asking you for confirmation and the card machine being covered up.
So if I'm a little dead behind the eyes when I ask you how you are, perhaps I've just had all those people turn up already that day and I just want to get through the last few hours of my shift so I can go home and stop pretending that all those insults and displays of rudeness don't affect me and let my customer service smile slip ... for the 12 hours betwen my shifts at least.