I think most people are both, I certainly notice it as a developer, times when my head is in the right place and my productivity goes through the roof and then

I think most people are both, I certainly notice it as a developer, times when my head is in the right place and my productivity goes through the roof and then the downtimes where it can be half that. I think it does tend to coincide with how busy you are, if you have too much time to think that's all you tend to do, over analysing tasks rather than just getting on with it.