ONE THING I learned from owning and running a service-oriented company for several years (janitorial -- for me, a much less stressful job than teaching and paid better too) is that giving one hundred percent, striving for perfection, is a mistake. It is inefficient. Diminishing returns are a fact of life in any endeavor; I found that I could do, oh, 95% of the 'perfect' job in 50% of the time (to use somewhat random but reasonably accurate figures).
Of course, the arts are a whole nuther matter though even there getting a reasonably good result in relatively short time certainly beats missing a deadline or making folks wait. I'm talking commercial work here, naturally. One can waste time endlessly on ones own self-indulgent pastimes!
A corollary to this would be my solid belief that this country (or any country, for that matter) was made 'great' not by hard work but, rather, by lazy people trying to find the easiest way to get things done. I've always been good at finding the most efficient way to get things accomplished quickly, working out work flows and routines. I found myself working out the best way to move my hoses around for watering yesterday (I've only one hose bib to work from) which started me thinking about this.
So, what does one do with ones saved time? I could just sit and relax but, well, I hate to sit and relax. So I guess I do my work more efficiently so I can...do more work? Sheesh...