Katana_Gelder, oh the joys of administrating for a "professional agency."

My old employer ran continuing education conferences for medical professionals. I have never seen people behave so irrationally or rudely in a professional setting as when we organized our annual national conferences. Two examples:
Example 1: We gave out official tote bags containing registration information and goodies and soon as the participants signed in. That meant that a lot of people were carrying matching bags all week. The participants would put their wallets, phones, keys, etc. in the bags, so you would THINK they would keep them with them at all times. But one afternoon, one of the participants came up to the registration desk and SLAMMED his tote bag on the registration tables, nearly whacking one of my coworkers in the head. (She ducked.) and the following conversation ensued:
Rude Participant: THIS ISN'T MY BAG!
My Boss (calm): OK, whose bag is it?
Rude Participant: (Yanking out the wallet inside and tossing it at us, actually hitting the coworker who ducked before.) I don't know. YOU look at the ID.
My Boss looks at the ID and takes the bag behind the registration desk while the Rude Participant rants, "I left my bag in one of the session rooms and went to the lunch buffet. When I got back, it was on a different chair. I just opened it and someone else's stuff is inside!"
Please keep in mind that lunch was hours before, so this guy had carried around someone else's bag for about five hours.
My Boss: "First, this is a huge hotel in the middle of a major city. We can't control who walks through this area, so we definitely don't recommend leaving a bag with a wallet and phone in it unattended. And second, when you couldn't find your bag why would you take someone else's and walk off with it?"
Rude Participant: (shocked and appalled) "Well, there's no reason to be RUDE about it!"
We finally got the guy to calm down and take his bag, which had been turned into the Lost and Found. And then a half-hour later, another participant (the one whose ID was in the "misappropriated" bag walked up to the desk, fuming, "Where the hell is my bag?!"
I swear, I thought my boss was going to thump her head against the registration desk.
Example 2: Our conferences were generally intended for our members, but non-members were allowed to attend - paying a much higher registration fee than members. (There had to be some incentives to membership!) Also, most people registered for the conferences months beforehand, and we offered a discounted "early bird" price for those who registered by a certain date.
Extremely Rude Participant (ERP for short) who was not a member, demanded on-site registration, but he didn't want to pay the higher non-member price. He also wanted the early bird discount, which had expired two months before. Now, keep in mind, the hotel sold out a month before, so if he had a hotel room (which he did) he knew he was going to attend the conference months before. He just didn't bother to register for the conference. He handed us a check already filled out for the member discount and early bird registration price and when we told him that wouldn't cover his registration, he commenced hollering obscenities.
My boss, whom I LOVED, immediately took over the situation to shield us employees from this guy's screaming.
ERP: I can't believe this BULL----! Just take my check! That is your job, isn't it? Or do I need to go to (Uber Boss, who supervised Boss) to report your incompetence? Uber Boss is a close personal friend, you know!
Trust me, we knew all of Uber Boss's close personal friends. ERP was not one of them.
Boss: Sir, I'm happy to help you, but you have to stop abusing me and my employees. Now, I can't give you the early bird price, because that expired two months ago. But if you want to sign up for membership here and now, I can give you the discounted membership registration price. Membership is $XXX per year. (About the same price difference between the non-member and member registration prices. So if he paid the membership fee and the discounted registration fee, he really wasn't going to save any money. He was pretty much going to pay the same amount either way. But if he attended other events, he would benefit.)
ERP: So I pay the membership fee, and that includes the registration for the conference?
Boss: No, you would pay $XXX for the membership fee and then $XXX for the discounted registration fee.
ERP: But I don't want to pay that! I just want to pay the member registration price!
Boss: That won't be possible. We reserve that price for our members.
ERP: (slamming his fist down on the desk) But I JUST want to pay the member registration price!
Boss: We'd be happy to charge you the member registration price, after you pay the membership fee for the year.
ERP: (slamming his fist down on the desk) But I JUST want to pay the member registration price!
Boss: That won't be possible.
ERP: (slamming his fist down on the desk) But I JUST want to pay the member registration price!
Boss: You can either pay the non-membership registration price, or you can leave.
ERP: Fine, but I want the early bird discount.
And convincing him that we wouldn't do that either, was a whole nother screaming match. Keep in mind, he was doing this in front of a room full of his peers. People he would want to network with, possibly author journal articles with, etc. You would think he would want to behave civilly.
ERP ended up causing another huge scene in the hall a few days later when he was not allowed to attend a special session that was not included in the overall conference package. You had to sign up for the special session months in advance because it filled up quickly. We were already at capacity, but ERP refused to accept that and stood in the hallway screaming "this close" to my boss's face because she wouldn't add him to the session. She finally just walked away from him.
Later, Uber Boss said ERP had approached him and asked why UberBoss's staff was so terribly rude to him. Uber Boss said we should try to be nicer.
We all kind of hoped Boss would thunk ERP's head into the registration desk.