Generally speaking, people who are not welcomed back as customers are in fact problem people....aka, people with too many issues for their own good.

How many times has Dan painstakingly explained his phobia about being "overcharged" for some small item or being "mistreated or dissed" by someone of authority in person or on the phone....only to waste huge amounts of effort and spend days chasing his loss?

It isn't too difficult to see why these things keep happening to him. Some people have these type of annoying personalities--that's all it is. They go around always feeling entitled to getting special treatment, getting more than the other guy, and they live their life in "paranoid mode" always thinking that other people are doing to them what they take enormous pride in doing: taking advantage of others in some way, shape, or fashion.

So for Dan to persist in this fantasy world of being overcomped, it seems all too normal and it won't change. When someone lives a life totally based on conflict, you're gonna be fed a constant flow of this type of goofy stuff.