Behavior is purposeful (even if we do not know why or how ) we act for a reason. There may be triggers that you are not aware on consciously but subconsciously. When you are tired and stressed out, you want peace and quiet. When someone is intruding that/your personal space, that is a trigger. When an expectation that you have of another is not met in your mind, that is a trigger. If someone reminds of even subconsciously of someone else that had made you angry, that is a trigger. You may want to look back and recall how your mother and father had expressed anger (of what you recall) Our behavior is also learned as well as genetically influenced.
If you are not doing the anger management classes, there are other options such as hypnotherapy, counseling, self help bibliotherapy and workbooks. Anger therefore, serves a purpose (even if that purpose is unhealthy or unsafe or even ridiculous.)
Anger: Wisdom for Cooling the Flames by Thich Nhat Hanh (Paperback - Sept. 3, 2002)
Hypnosis for Overcoming Anger (Hypnotic Empowerment Series) by Janet I. C. Decker and Hypnotherapys Services (Audio CD - May 17, 2007)
The Anger Workbook: A 13-Step Interactive Plan to Help You... (Minirth-Meier Clinic Series) by Les Carter and Dr. Frank Minirth (Paperback - Nov. 25, 1992)