In your book with Dr. Fitzgibbons, Forgiveness Therapy (2015), you focus on the initial emotional reaction as unhealthy anger. I feel more sad than angry and so I am wondering why such a heavy emphasis on anger in particular.
In our experience, we do see that some people present with anger, some with confusion, some with mild anger, and some with a burning hatred. So, you are correct that anger is not the exclusive presenting emotion. Yet, it is excessive anger that most concerns us because of the scientifically-supported relationship between deep, abiding anger (unhealthy anger) and the development of other psychological symptoms such as anxiety and depression. See for example, Vidal-Ribas, P., Brotman, M.A., Valdivieso, I., Leibenluft, E., & Stringaris, A. (2016). The status of irritability in psychiatry: A conceptual and quantitative review. Journal of the American Academy of Child and Adolescent Psychiatry, 55, 556-570. When a client presents with a pattern of unhealthy anger because of unjust treatment by others, and if the person chooses to forgive, we do recommend Forgiveness Therapy as the treatment approach so that psychological symptoms can decrease.