How to learn human psychology? and Why Learn it?

MY ANSWER to the 1st part: By not following social media influencers, or take their rants seriously ... by reading the original scholars like ( Carl Jung, James Hillman, Marion Woodman, Richard Schwartz, Peter Levine, Bessel Kolk, Stephen Porges, Bruce D. Perry etc. ) and evaluating and comparing each and every line you read with your personal insights gained through intuitive self-exploration of your internal experience! put any thing you read on hold if it doesn't match with your intuitive self-reflection ... your or other's over reactions, triggers and fears can also give indepth insight ... 

Discard any experts or school in psychology who explicitly reject the existence of human soul or is grounded in purely materialist world view ... 

And do not go near Freud, at least in the beginning, and even if you read him, do that from purely from an academic perspective ... 

I have found Jungian psychology to go toward depths which other schools of thought in psychology are not even aware of ... but of course one should keep wearing their critical lenses while reading any school of psychology ... 

Up till now I have found the work of Jungians (Jung himself, Hillman, Woodman, Franz etc) and the work of Trauma psychology (see Peter Levine, Bessel Kolk, Gabor Mate', Stephen Porges) and the original work of Bruce D. Perry in Neuro-sequential Development, and the work in the domain of Islamic psychology like that of Abdullah Rothman to be overlapping and converging toward some common points, which also aligns with my own intuitive reflections on the subject ... 

Now, Why learn it?

Don't we deal with humans all around in all shapes in sizes, in family, at work place, on the road, etc. if we have a better understanding of how their hearts, minds, souls, brains, guts, bodies are all working together, then we can save ourselves and others from a lot of trouble which we otherwise unintendedly get into ... and I can bet that our understanding a.t.m about who we are, how we function and how others function is profoundly limited and is already causing lot of troubles perhaps everywhere for almost every person around ... leave others aside for a moment, self-awareness - I have come to believe - is critically important for our personal well-being, and also to strengthen our connections with our Creator ...