You've already figured it out. It is your behavior management skills that are the problem, including your difficulty maintaining your equanimity. See my response to "Help with 4 year old" and folllow the suggestion. You are experiencing precisely the same problem that the other family is experiencing.
You gave me some sound advice regarding my 4 year old. Now what should I do as a parent with behavior management issues, so that I can help my daughter with her behavioral skills? Therapy? Books? I just want to raise a happy child, and I do not want to create the same issues on to my 2 year old as well.
Apply the strategies you'll find in SOS and you'll be fine. It's sound behavior management that's called for, not therapy.