I think it is also related to the fact that much of what software developers do is a waste of time. By this I mean that if the app or service was specced correc

I think it is also related to the fact that much of what software developers do is a waste of time. By this I mean that if the app or service was specced correctly the first time (by the end-user or project manager knowing what they wanted) then there wouldn't be so much backtracking or code getting thrown out. All that wasted effort tends to make one question what they're doing with their life and makes them grumpy. The problem is that your actual job is different from what the people signing your paychecks and writing your performance reviews tell you it is. You only think your job is to write code as specified. Really, your job is to make whatever people need to happen, happen. Not what they want, and not what they say they need. And so when you build what they say they want, and it turns out to not be what they actually need, you have to rebuild it differently. Supposedly "Agile" fixes this when done right, but I get the feeling that doing Agile right is about as hard as finding a true Scotsman. :(