I think therapy is somewhat mysterious because no matter how many schools of psychological thought or therapeutic practice the therapist or pdoc uses, the human mind, and therefore our thought processes and emotions are still largely a mystery. With all the medical advances the 21st has brought, there are still chemical interactions/bodily processes that science cannot explain, for instance, what initiates the birth process?

I think a T can be thoroughly schooled in Jungian, Gestalt, EMDR, DBT, CBT, Existentialism, etc., but most of the time he is judging moment by moment what is emerging from his client's mouth and then quickly judging what direction to zing off in with his answer. And sometimes they don't know what to say - I can always tell when my T is stuck - he will say something along the lines of "This may sound totally crazy but tell me what you think."

As for therapy being mysterious? I don't think it's all that mysterious - I know from doing my practicums that 95% of being a good therapist is simple learning to shut up and listen, then listen some more. The trick is to remember that clients enter therapy subconsciously knowing the answer to their problems. The trick is to get them to open up and verbalize - so, not that mysterious at all.