I was in a similar situation recently at, surprise, Wal-Mart as well. My brother and I were going to go fishing, and he needed a license, so we were at the Sporting goods desk in the back.
It was about 7 or so in the evening, and there was a young fellow in front of us, late twenties to thirtyish. He was fairly fit looking, maybe 5'9", trim, had a folding carpenters knife on his belt. Hat on his head, head appeared to be shaved clean underneath. I couldn't tell if he was/had been sick, or if it was just shaven.
There was some sort of problem with the transaction that required a Manager to override. The clerk, a 17-18 year old girl had paged for a CSM to come back to the sporting goods counter. I didn't think much of it, figured a CSM would be over in a minute and we'd all be on our way. After several minutes she either paged or phoned the office. I've forgotten the order it went down in, but I think she paged for a CSM twice, and seemed hesitant to page again, and so she called the office, I think again twice. We stood there for probably close to ten minutes though. By then I was getting ******.
At the CSM though, for leaving the girl hanging like that. I'd been watching the guy all this time and I was getting more and more antsy for a CSM to GTF over there and resolve it, he was making me nervous.
Unlike KingEdward's though it wasn't an outward show of anger or verbal abuse. He was quite and feigning politeness. Or trying to stay polite. But you could see he had a certain tension in him, he was wound up and getting more so as time went on. It was building and he was just holding it in.
I'm sure a lot of us do that, but he was making me nervous. I don't know what it was, but he was getting me pretty taunt and wound up myself. In reflection part of it was his funny way of standing mostly very still. Try doing that for minutes on end, it's not natural. Towards the end he did start pacing around a bit, I don't remember if he was clinching his hands into fists while standing or not, but I do remember him thumping the counter a time or two with a closed fist about 8 min in or so. He was still very contained though, in that it wasn't really directed at anyone.
I didn't have a CCW on me. I had a Ti-lite, I always carry a knife, but in a tool capacity. Sure they will act as a self defense weapon if you have to, but that's not why I carry them and they aren't what I turn to first. In this case I just reclined myself on the shelf of baseball bats behind him and watched. If the SHTF I had a nice bat all picked out, and I was also trying to act as a barrier between him and the bats, kind of keep them out of sight out of mind, no need to tempt the fellow.
It blew over very uneventfully though. At the end of the ten minutes or so, he suddenly told the girl very politely, "I'm sorry, I know this isn't your fault, but I just don't have time to deal with this right now" and walked out the automotive exit. My intuition was he knew his boundaries and had reached a point where he wanted to leave
before the CSM showed up and he reacted by ripping his head off or otherwise going ape on him.
The clerk processed my brothers license and we left, there was still no CSM in sight at that point. I was a bit drained myself, typical letdown from a stressful situation, and was tempted to wait for the CSM and let loose on him myself but I figured stupid is as stupid does. If he keeps up that bad of service he might learn putting the baseball bat display on the shelf by the checkout counter might not be such a good idea.
I really felt that the CSM had put the clerk in danger by taking so long to respond. I also felt I had been put in danger by proxy. I was not a happy camper when I left.