Paul Caron of Taxprofblog has a roundup of the extensive commentary(including two of my own posts) stimulated by his post arguing that law professors tend to be "miserable." He also seems to modify his original claim somewhat:

Much of the commentary argues that law professors have a great job and that most are happy with their jobs. I agree with both points -- my modest question is that, given how great this job is, why are some law professors so unhappy?

The answer, I think, is that some people in virtually any job are unhappy. There are people in all walks of life who are unhappy for reasons having little or nothing to do with their jobs. For example, I'm somewhat unhappy right now because I'm recovering from ankle surgery and can't walk; that has nothing to do with being a lawprof. And even the best jobs are going to have some incumbents who are unhappy because they are temperamentally or otherwise unsuited to them.