Following on from a comment to Question 4, the following quote from Jung comes to mind:
... the principal aim of psychotherapy is not to transport the patient to an impossible state of happiness, but to help him acquire steadfastness and philosophic patience in face of suffering. Life demands for its completion and fulfillment a balance between joy and sorrow. (Collected Works, Vol. 16, p. 81)
I think this is a very difficult point to accept in our time which has seen the advent of the psychology of happiness and what seems like an expectation that if there is suffering, it must be bad. But Jung understood that suffering has meaning, brings depth to our lives, and is a necessary part of life.
Now to question 5:
5. What is the toughest part of being a therapist?
There are several aspects of being a therapist that are difficult:
-- the patient who comes and is someone you just know you would love to have as a friend and yet, you cannot because we take on an ethical responsibility to be in a very different kind of relationship, one which does not end for us when the treatment does, because often patients decide to return later, even years later.
-- letting someone you have worked with, sometimes for years, go knowing that you likely will never hear how things turn out for that person. We truly have to allow our patients to pass through our lives. Therapy is an intimate relationship yet we have to let it go when the patient leaves.
-- we can't casually talk about our work at the dinner table -- or anyplace else. We are charged with carrying other people's secrets and that can become a heavy load.
-- for those of us in private practice, there is the anxiety of being self-employed which must be held separate from our work with patients, so that we do not hold on to someone because we are afraid of losing the income.
-- the increasing turn to medicalizing emotional problems leads some patients to expect that change should not take work.