Why do I react so strongly to my boss?

You are seeing something important: your reactions to bosses carry more weight than this job alone could explain. That means something older is riding along, some early lesson about authority that you learned long before you ever had a manager. Noticing this is the beginning of getting free of it. When a person in charge sets off a reaction far bigger than the moment deserves, it is usually because they have stepped onto an old bruise. The current boss becomes a stand-in for a parent, a teacher, whoever first taught you what power feels like. It is not really about the email they just sent. Next time the strong reaction hits, pause before you act and ask one question: how much of this is about the person in front of me, and how much is older? You will not always know. But the question itself creates a gap between the feeling and your response. In that gap is your freedom.