Unfortunately, the stress can be more than some people can effectively manage and it comes out in an inappropriate manner at the most unopportune times. Controlling your anger, can be one of the most difficult challenges you face in self-transformation; however, if you want to have a fulfilling life it is a challenge you must face head on.
The easiest way to control your anger is by removing yourself from situations that are known to cause your strife. This is an external change and is not always the best or even a readily available solution.
Another way is to keep a journal. While this may be beneficial in the later stages of anger management when you are first starting out, keeping a journal is a delayed action and will probably not give you much help in the heat of the moment.
The third long term strategy is to seek medical help. You could try acupuncture or talk to your health professional. There may be something going on inside your body physically that manifests itself as rage. If your primary care physcian cannot find a physical reason, then you may want to speak with a therapist.
While these are all good long term strategies most people need something they can do right now, today. The following are those suggestions:
Smile. Sounds silly I know, but when you are in a stressful situation such as a heated conversation with your boss, the best thing to do, is just smile. Stop talking shrug your shoulders and smile. Now this will not immediately calm you down, but it will help diffuse the situation until you can get to a corner by yourself.
Many people suggest venting. This is actually an acitivity that could do more harm than good. By venting, you are reliving that moment over again and each time you tell the story, it gains more power over you. Instead of venting, go partake in your favorite activiity. Listen to your favorite song, visit your favorite website or forum, stretch, crochet, chew gum, etc. The idea here is to start doing something other than focus on the situation that just occured. You will find by engaging in a different activity, one you enjoy, you will be able to put your anger aside quicker than if you continued to focus on it.
Finally, make sure to engage in an appropriate physical activity. Some people take up boxing, go to the batting cages or some other sort of physical demanding sport where aggression is expected.
Finding the strategy that works for you will take time. It may be one or a combination. Keep trying different techniques until you find the one that works for you.