Imagine that you went outside and jogged for 10 minutes. This would be a healthy thing to do.
Now imagine you went outside and ran for 20 minutes. It'd also be healthy, but it wouldn't necessarily be twice as healthy as the 10 minutes.
What if you ran for an hour? Well, you'd definitely push yourself, but chances are you'd still see most of the benefits from those first 10 minutes of exercise.
Exercise has diminishing returns for the simple reason that your muscles tire out. And as your muscles tire out, their ability to be stimulated for further growth diminishes until it's more or less non-existent. Spending two hours in the gym gets you little to no extra benefit as spending an hour. And spending an hour only gives you slightly more benefit than spending 45 minutes.
Most work is this way. Why? Because, like a muscle, your brain tires out. And if you're exercising your brain by doing any sort of problem-solving, or important decision-making, then you're limited in how much you can effectively accomplish in a day.
My wife used to work in the advertising industry and, like many industries, there was a fetish for working insane hours, especially when a major presentation or campaign proposal was due. People would stay late, often working until 9 or 10 o'clock at night. Sometimes they would come in on Saturdays.
But she noticed that most of this extra time was pretty ineffective. The four hours at the end of the day, from say 6 PM to 10 PM, contributed about as much usable work as the first two hours of the day. People were essentially slaving away for marginal benefits.
And in worst case scenarios, people would start producing bad work or make bad decisions because they were so tired. And when you accumulate enough bad work and bad decisions, you actually unintentionally create more work for yourself. So you go from working for diminishing returns to working for negative returns.
You dumbass, now look what you've done.
This happened to me when I started working on The Subtle Art. I was hanging out with a few other writers and we'd get together for "write-a-thons" and bang out as many words as humanly possible in an afternoon. It was basically one big pissing contest where we'd gloat about our word counts over drinks later that evening.
My best day was 8,000 words, all in about 6 hours of total work.
"Holy shit!" I thought, "I just produced 32 pages in a single day!" All you would need is 10 days of that kind of productivity to write an entire book.
There was just one problem.
It all sucked.
I mean all of it. When I eventually went back to revise the chapter a few weeks later, out of those 8,000 words, there were maybe 500 that were usable.
The problem is that it took me four days to sort through all the garbage, re-write the few parts that were salvageable, and make the decision to delete the parts that just sucked.
Suddenly, my 8,000-word burst of "massive" creativity created so much extra work for myself that I would have been better off not writing at all that day.
This was a huge realization for me. When it comes to creative work, not only is there a diminishing return, but at a certain point, writing more produced a negative return. Because bad writing isn't just bad—bad writing creates more work for yourself, because it requires way more time to revise and edit.
I spent most of the first year writing The Subtle Art with this mindset of "more = better." As a result, looking back, I spent at least half of my working hours fixing the messes I created unnecessarily in the first place.
Eventually, after months of frustration, I began to notice that most days, everything I wrote in the first 1-2 hours was great. It needed little revision and usually fit quite well with the message I was trying to go for in the book.
Everything written between 3-4 hours was mixed. On good days, I'd produce some good content (although almost never as good as the first two hours). But on bad days, most of it wasn't usable and I was creating more work for myself.
Pretty much everything beyond hour number four sucked. Past that, any writing I attempted had negative returns and I was strangely better off playing video games or something.
It wasn't until I had been writing for over a year that I worked up the courage to try limiting my writing to two hours a day. I was still so stuck in the mindset of linear returns, and I was so invested in this monstrous mess of a first draft (125,000 words, and most of it was shit) that I was afraid to find out that literally 50+% of the previous year's "work" had not only been pointless, but had actually made me less productive.
But I tried it. And my god, did the book just shoot out of my fingers like my undiscovered Jedi powers. I banged out a new draft of the book in two months flat.My guess is that most creative work operates on a negative returns curve. I know in the past when I've done design work, I've tinkered with an image so much that I can't even tell if it looks good or not anymore. I would then spend half the night trying to make it "look right," only to wake up in the morning realizing the idea sucked in the first place and I was better off starting over.
Work that's highly social or requires a lot of team building can produce negative returns too. If you always need to be on point, then whenever your energy or mood slips, you might actually end up repelling customers, costing you potential long-term profits. Micromanaging the hell out of your employees won't only not make them more productive, they'll come to hate you and be even less motivated to produce results for you in the future.