I think a lot of it is a certain sort-of hypnotic quality about certain kinds of work. When you start dreaming in programming languages, or about talking with customers, etc. you are trying to hard, and it's bad.

In this case the best thing to do is to scale back. Start a hobby of something else (it doesn't matter what but it needs to be very different) and assign some time to it every day. Maybe it's gourmet cooking, or woodworking, or growing your own food.