This post (Programming first principles - 7. Premise - Complexity increases exponentially with scale) was originally published on Sargalias.
This premise reminds us that complexity increases exponentially with scale. See Programming complexity.
As the number of entities in our code increases, the possible number of interactions between them increases exponentially.
In other words, any insufficient or imperfect processes during development will have an exponentially negative effect later.
Our solution to that must be that we always keep complexity as low as possible, to minimize the effects of its exponential increase as the system scales.