I used to work with someone I did not like. To be in a meeting with him drove me crazy. As soon as he spoke I began to squirm and eventually to seethe. No matter that a lot of people agreed with me that this guy was a "jerk", I knew that my reaction was out of proportion, and I had to work on it to see what it said about ME. I sat with it for several days, trying to narrow my distress down to a single characteristic that bothered me. I eventually realized that what really got my goat was that (I felt that) he was lazy. And even worse, he got away with it. No one challenged him or made him do his fair share.
Once I had gotten to the crux of what characteristic irritated me, I had to turn it back on myself. How was I in the laziness department? The opposite. Miss Compulsive Worker. Stay up all night to finish a project. Do it myself rather than delegate to someone else. Haven't allowed myself to take a non-working vacation in 15 years. Suddenly I realized that I was actually jealous of this man. He was "lazy" and I never let myself even relax. I'd stumbled onto an idea of who I was and how I had to be busy, productive, compulsive. As soon as I realized this, my excess emotion at him dissolved, and I was able to leave "him" and go back to work on me.
Anger is a very good koan, enabling us to step back a little from our self- notion and see where we are attached. Do we have to do anything about what we discover? I don't know. Depends. Often just stepping back to see something is enough. Often just becoming aware of something, like a little piece of our notion of self, means the beginning of the end of that something. Many koans show evidence that Zen teachers used anger skillfully to poke at their students' addictions, unbalance them and help them step "off the top of a hundred foot pole".
Another example. A student came to me in sesshin, unsure if she should work on Zen koans because she was a Catholic. I asked her if she had any questions within Catholicism which were bothering her. She said that she had been worried over the question "Is there anything outside the will of God?" Perfect koan! She 'worked intently on it all sesshin. In Zen terms we could re-phrase it, "Is there anything outside of Buddha nature?" Is jealousy outside the will of God? Is child abuse outside the will of God? Is a toilet brush outside of Buddha nature?

Jan Chozan Bays