Well, understand the triggers itself, you have to be self aware without lying to yourself. Do you feel fear? Why? Do you feel anger? Why? You do feel all of this, but this happens really fast and you don't have a lot of choice. It will probably happen. You must accept the pain that is already in you for now and don't worry. If it is the fear, aknowledge it, but don't do anything to change it, because it is programmed anyway because of past events. It's basicly the meditation I'm talking about, because it applies the best based on what exactly you want to know. But that's just one part - if you want to really get rid of those feeling, you can't get rid of them with awerness of what is being felt, but with talking about how you felt when this originaly happened and looking into the eye of fear that doesn't exist - this is done in therapy.