This is the sort of thing that is obvious once you think about it, something we all know, but we tend to forget as problems crop up in our relationships with our fellow humans. More information about what isn’t working might not help, the proper way to deal with each other is still “conjecture and criticism”. This is why it is valuable to keep communications alive in all your relationships, coupled with the idea that you can question anything and you might just be able to build understanding. Not solve the mystery, just work towards being less wrong.
Keep in mind this is about strengthening relationships between two or more people who have compatible goals and ideals. People who don’t have common goals, or even a common understanding of the world will need at a minimum a desire to understand each other.
People are not a means to an end, they are ends in themselves, this is the cause of the mystery. If all you needed to understand someone was to know everything about them, then they would have to be static puzzles with a finite number of pieces, instead of the dynamic mysteries we really are.
