It's a relationship with a professional helper. The rapport you share with them is the fundamental aspect to the therapy. They must maintain their therapeutic boundaries in order to remain effective as a therapist. You may feel otherwise toward them, but this is transference and that's okay, it's all part of the therapeutic process. If the therapist were to view you as a friend, however, he would lose objectivity and be unable to provide effective therapy.

I agree with everything and would add that the therapist can also have transference and do therapy-interfering things

Hellboy