First off, by all means, keep reading "clients from hell". If you're just starting out, it's a great way to figure out what the red flags are when dealing with prospects. If you've been going at it for a while, it's a massive stress release to see that it's not just you.

That being said, whenever I get into discussing this, I tell about how I went to my hairdresser (a fairly outspoken man) a while back, and while he was cutting away, I asked if he could cut it a little more in the back. He replied simply with 'no' (later explaining it). I accepted that in the instant, recognizing the parallel, yet most people (web developers and non-web developers alike) think I should've forced him to cut it as I asked. Some even get angry when I suggest that my hairdresser could do anything he want (within my given requirements), because I am paying him for his expertise. Their reasoning is that because I pay them, they should do anything I tell them to. I suspect therein lies the difference between bad clients and good clients.