A lot of "best practices" are developers who make code complex in order to attain some level of architectural purity for its own sake.
An example of this I recently experienced was trying to understand and debug what should have been a simple integration app, but where a ton of injected commands and queries were used to implement the functionality. Following the logic was painful as the code was completely atomized for no particular reason. Worse, real-world concerns, like proper logging, were ignored.
I hate to call this an "autism tax", but perhaps there's something to the term: many intelligent developers, especially left unsupervised, tend to pursue highly abstract solutions, to what should be straightforward problems in order to satisfy a compulsion for order and symmetry.