Trying to reason about postgres is somewhat of an enigma when you are forced to do it; generally the only reason as a programmer you have to is because something went wrong, and then the mindset is a mix of nervousness and panic; then incredulity at some of the seemingly unintuitive behaviors. I suspect this might be true of any large, complex system at the edges.
With postgres I think it's also the problem of weak observability mechanisms. By default all you get is cumulative statistics. Then with extensions you get pg_stat_statements and a few more things, but you really shouldn't need to use something like pgAnalyze to get basics, like history of autovacuums, cumulative wait events and other stuff like that.
