So, I used to work for Wal-Mart as a cashier. One thing I'll preface this with, is that cashiers have almost no contact with the other departments. So, when Dr. Customer got into my line, during a busy time of day, I was quite startled to find a sales floor associate, squeezing through the line behind me to warn me about her.
She had, apparently, spent the last four hours demanding the sales floor associates bend to her every whim, having reported them to the managers for so much as forgetting to smile for a moment, threatening to call lawyers for one out of date box of cereal being on the shelf, etc.
So I nod a little, and thank the associate for telling me, and proceed to take care of my line. Now at this point, Dr. Customer is already looking at me with suspicion. I try to ignore it, and take care of the person in front of her, and she mutters some vitriol about how she would have been out of here if I hadn't been chatting with my boyfriend--the other associate. I grit my teeth and ignore it. She starts conplaining that I was talking th the other customer too much (I had told them to have a fabulous day, and thanked them for shopping with us).
So I apologise to her for the wait, and she snaps, "Stop talking, start scanning." Nevermind that I was already scanning. I focus on my work, and she demands to know why I didn't choose to have a bagger. I informed her that it wasn't an available position.
This goes on with various complaints throughout the transaction. We come to the payment part, and she takes out a gift card, and looks me in the eye and tells me, "You have to run it as a shopping card."
I nod, take the gift card, and hit the gift card button. She leans over my register, and this look of anger passes over her face, and she says, "Why are you running it as a gift card? i told you, it's a shopping card!"
I inform her that the two are synonymous, and she goes on a whole massive rant about how she knows there's a shopping card button, and she's not stupid, she has a PHD, while I have customers waiting. Meanwhile, I ran her payment, and it went through just fine. She was still complaining when I started loading her groceries into her cart, and immediately turned toward the customer service counter to complain.
She got not four feet, when the cheerleader in line behind her loudly said, "God, what's her problem?"
Before I could even respond, Dr. Customer turns around, hands in fists and looks at me like she wants to murder me, and screams, loud enough for the whole front end to hear, "Excuse me?! How DARE you talk about me behind my back!" She demands to see my manager.
So I call her over, and she tries to defuse the situation, and Dr. Customer goes on and on about how incompetent I am, and how I was talking shit about her to other customers, even going so far as to stare down this now terrified cheerleader as her teenage friends, and demand to know if I was talking shit, trying to use the fact that I was standing there and intimidating them as an excuse why they sided with me.
It was a total shitshow. The customer ended up getting store credit (on her shopping card), and I got a write up.