I don't think it's underrated; it's that it's hard to write. You almost go full-circle. You start off writing highly procedural code (with too much branching),

I don't think it's underrated; it's that it's hard to write. You almost go full-circle. You start off writing highly procedural code (with too much branching), join the GOF-all-the-things religion and eventually revert to highly procedural code (more specifically "algorithmic code" or "functional code"). As an example, many years ago I wrote a dependency resolver. It needed to find cycles (as we had some rules that could resolve those cycles) in order to make changes in the correct order. At the time I was a junior developer in that problem space. My solution consisted of an O(scary) algorithm; consisting of classes, patterns and all the good things that make your code "simple" and "understandable" (it was not). Customers eventually threw graphs with a few million edges at it and we needed a new solution. I have no idea how I happened upon Tarjan's Strongly Connected Components Algorithm but some hundreds of lines of code was replaced with dozens. Minutes turned into milliseconds. Here's the thing about simplicity: even though the code was simple, even I (as the author) didn't understand it at the time - I trusted the guy with the PHD. Many years later I finally understand how it works. It is an incredible masterwork of simplicity but as it turns out something that is simple is not always understandable. Simplicity probably has a simple definition in the dictionary, but in practice it can be quite complex to make something simple. So you can't just say "make your code simple" because it's really hard to do that.