The way our minds work is complex with multiple things going on at the same time. When listening, part of your mind is processing what is being said, part of your mind might be flitting from one thing to another and another part, that you are not aware of, is keeping your body functioning.
The two parts we are interested in are the rational mind, located in the pre-frontal cortex, and the emotional mind, located in the amygdala. Your emotional mind is probably quite quiet at the moment and your rational mind is processing what you are reading. But that can easily change if suddenly you feel under attack. The emotional mind’s job is to keep you alive by triggering a fight, flight or freeze reaction. It’s the oldest part of your mind. It’s impulsive and very strong, much stronger than your rational mind. In a modern world, we are less likely to come across the dangerous situations that our ancestors did, but the same reaction is triggered by smaller threats or situations.
The rational mind is what makes us human. It’s used for relating to people, planning and working with concepts. It’s the part of our brain that we need to engage to have successful conversations. And it works well when the emotional mind is quiet. But when the emotional mind gets triggered, the rational mind gets swamped and a difficult conversation is likely to go downhill quickly.