Honestly this post was a great read.
Personally I don't believe in a shadow self just in pure nature, its all survival strategy.
When some one approaches most situations with violence and aggression its because they have found it to be on average a succesful strategy, where someone approches life with cold logic its because on averages being able to remain calm has been successful for them.
Just like evolution these modes of thought and action are under pressure of survival of the fittest.
The shadow never really has to be illuminated as long as it remains useful, my personal term for it all is functional truth.
Selection is valid way of looking at things as well @shai-hulud. It can be understood this way, afterall, nature gave us techniques for a reason — denial, for instance, can save your sanity (but it can also keep us dumb.) I agree we don't have to illuminate it all or analyze it to be functional or thrive. But I also think that the subconscious is a lot like inside of a car. If you tinker with it and don't know how it works, then you can do damage. And if you do take the time to know what's going on under the hood, you can sometimes upgrade it, fix it, etc. So it could in a way be evolutionarily advantageous for some to be are of the intimate details of their truth.