I'm sorry you had to endure that and put on a smile and be cordial through it all. It can be very tough.
I've run into a few here and there. I work in the utility industry, dealing with individuals, builders, dealers, etc. Most people are understanding and at least cordial. I try my best to do everything within my power to accommodate within reason. I do it because I enjoy helping and most people aren't shit weasels, but are just going through a rough patch and I happened to be the next "bump in the road."
When I do run into the infrequent shit weasel, it's truly a comedy you want popcorn for while you watch. When they've reached the point that I'm no longer willing to help them, I have policy, procedure, and the Public Utility Commission rules right behind me. They will literally push me into a corner, and then I'll just step aside and let them literally beat their head against the wall that is government bureaucracy.
I'm actually proud to say that I can count the times that has happened on one hand. I agree that the current "Me first" culture and mentality that is being fostered is churning out more entitled people. While I hope they don't turn into shit weasels, only time will tell.