We all have emotional triggers. There are certain people (as well as events, places, and things) that, if you are not careful, can cause your blood pressure to rise. Perhaps it is the way they say something, or give you that certain look. Whatever it is we don't like it. Sometimes they do it on purpose, and sometimes they don't.
It is your responsibility to analyze your triggers. What is it about that person that unnerves or annoys you? Once you figure it out, the next step is to plan your response. Yes, plan your response. Have a set answer ready for that person every time you are around him (or her).
You have no control over another person's behavior. But you do have control over your own. If someone does something that unnerves you, how you respond is your choice. Of course, this is the textbook way of doing things. If you are not a textbook kind of person (and I am not per se), then take heed to the advice my late grandmother, Essie Mae, used give to me when she would say, "Kelvin, you just make sure you do the right thing."