I've worked with difficult clients before, but this one takes the cake.
The worst exchange I had with them was when they wanted documentation for a particular software tool I'd written. No problem — I already had a Word doc ready. I sent it over.
10 minutes later I got a response: "This is too hard to read, can you make a diagram instead?"
At that point I was already a little annoyed, but whatever. The problem was, I didn't have access to any diagramming tool like Visio. But MS Paint could do boxes, text, and arrows, so I painfully made a diagram using Paint and sent it.
The response came back: "It's a little hard to read. Can you add colors?"
At that point I'm thinking "WTF is this? Kindergarten?" First we can't read text, we need pictures, and then pictures are hard to understand unless they have colors?
The constant back-and-forth and vague requests made the project exhausting. How do you communicate with clients like this who keep moving the goalposts without being clear about what they actually want?