I think most humans think simple. All our thoughts begin with simple things. When the simplicity cannot meet our needs, we add complexity. So, the next time you see something complex, know that the complex thing was probably not the first thought, but the thought added to the simplicity to meet the extended needs.
I think the same thing holds for software programs. We write them and try to keep them simple. If we feel to meet our requirements using the simplicity, we add complexity. I think if something needs to be documented, it should be the need for the complexity. Given all my thoughts, I wonder if KISS (Keep It Simple Stupid), stresses on finding the best simple solution known to us. I think, it says before you add complexity, evaluate other simple solutions.