One of my most arrogant customers was one that constantly called support because she could not get things to work as she wanted.

We repeatedly told her that she was working against the way the system was built and that was what was causing her problems.

This was not a custom system for that customer but a cloud product we where offering with over a thousand customers on and it was designed with a certain workflow in mind.

Despite this she always complained that the system was wrong and we needed to fix it.

She was also always late for her deadline complaining that she did not get the information from her bosses in time and demanded we help her get it done :)

But I was fortunate that everyone at our company held a unified position that it was not out fault that her bosses gave her info late or that she tried to do things in a way the system was not designed for.

So when she got to aggressive we just offered her to go somewhere else.

I thing they finally did, after about two years.