I get far to angry at certain people?

My father and brother irritate me beyond words, and they are the only two who do it. Everyone I know says it is impossible for me to be in any mood apart from relaxed and happy, and for the most part that is true. It takes a lot for most people to make me angry but my dad and my brother make me angry with no effort. My brother is okay most of the time, but I often find my self beyond angry with him and the things he says, as they are often immature (and I am the younger one)! But in many ways my father's presence annoys me! He sneezes and I get annoyed, he's constantly loud and obnoxious with no care for other people's personal space or feelings! He antagonises me, every day, to get me angry and it is getting to the point I cannot stand it any more. Whenever they make me angry all I can do is go to me room and wait until I calm down. Recently, however, my father has been antagonising me in public, saying things to anger me that he knows will do so, and I am not able to leave right then and there -- so how can I help calm down when he does anger me in public?