I understand the big book was written so others could work the program while not accessing meetings, but from my experience, the full effect of step 4 was experienced with that of a sponsor. Anger, yes, I had it, but anger is fear, what kind of fears where they? That was found through a long and thorough discussion with sponsor.
Now knowing the sponsor's part, I don't see how anyone can fully grasp the intensity of step 4, a self centered step; move on to 5 with a knowledgeable guide, and truly become other-centered... my experience was what I required for me. 6, 7, 8, then 9 with a sponsor's guidance, again, thorough explanation of 10, 11, and 12. Again, my experience was what I needed.