Once you have identified some of your triggers and have begun to understand your trigger themes, you will be able to be work more constructively to control your response to those triggers. Anger-triggering thoughts occur automatically and almost instantaneously, so it will take some conscious work on your part to identify them and to substitute something more to your liking.
For example, imagine you have just been cut off while driving on the freeway. Take notice of the physiological anger signs that tell you you're upset. Take a deep breath, and try to look at the situation rationally instead of going with your first impulse to attack. Instead of automatically assuming the driver that cut you off did it deliberately (which might be your first thought), consider the possibility that the other guy did not see you. If you can consider that the provoking action was not aimed at you personally or was a mistake, it will be easier for you to tolerate.
When you feel justified in your anger, you are giving yourself permission to feel angry, whether or not it makes sense for you to feel that way. The faster you stop justifying your anger, the sooner it will begin to recede. While all anger you feel is legitimate in that it is the reality of how you feel at a particular time, this does not mean that your choosing to act on your anger feelings is always justified. Remember that being angry is quite bad for your health, and destructive towards your important relationships with others.