We as devs tend to seek optimal solutions as if they were a simple numeric quantity, where more/higher=better. We know this is not how things are, but the mental model is seductive in in its simplicity.
What I have learned over the years is that it is the constant change between different forms of attention and focus that drive me to be my best. Which means time, real time, away from what I do for work. And when I return to work after doing so, I appreciate it all the more.
You might be interested in Mihaly Csikszentmihalyi's book, Flow, if you have not yet read it. Although it has nothing to do with game playing per se, it helped clarify many aspects of my thinking when it came to why I felt I was 'wasting' time while gaming, and why I was wrong in that assessment.