It’s related to what I think of as “coherency” and I’m often surprised at how long it can take.
The most recent example is that I was writing up some technical feedback for a reviewer of a product I develop.
My first draft was several pages worth of dense prose. I realized I needed to simplify, otherwise it would overwhelm the reader. I worked on it for several hours, and in the end I had it down to about 4-5 paragraphs.
So it took me five hours to write what looks like a simple, straightforward email!
I’m a music producer by trade, and the principal is very much at work. To create a successful recording requires getting into the small details of the sounds, and working with them, whether your tools are complex or simple.