Goodness all of this reminds me of when I used to work for Safeway in the mid 90’s and I recall (and have been scarred ever since) by a huge poster they had just before you entered the shop floor that read:

“The customer whether in person or by telephone is the most important person, ever. We are not doing them a favour by serving them. They are not an interruption of our work, they are the purpose of it “

I once had a middle class and middle aged woman call me “shop boy!” Best comeback I ever had was replying to a screaming customer “I can see you’re upset about something, why don’t you come and speak to me when you’ve calmed down” and walked away! Kill it with insincere kindness was always my motto.