I was going to call it “intellectually challenged” clients, but apparently that’s a real condition.
I’m referring to simply stupid. The ignorant, impatient, self-absorbed kind of stupid, often encountered in clever people.
Selling to this breed is difficult on a good day. All of the information is there for them, the options are laid out clearly and logically. And still they find a way to muck it up. Convinced of their superiority, they write an ALL-CAPS email to support to explain how stupid our site/system is.
These clients are a very small minority of course – and a good benchmark. Design and build with them in mind. Assume that the people using your site/system are stupid and hellbent on blaming you for it.
There is a limit here though. Some clients simply aren’t worth the trouble they cause. It’s good to decide beforehand what level of abuse you will tolerate. If a client consistently strays over the line, taking up valuable time and making you wish you hadn’t quit smoking, fire him.