Sometimes things that happen or things that people say remind us of past events that were very stressful or frightening to us, and we cannot really tell the difference between a present danger and a past one. There are reasons why a brain might need to identify a possible danger very rapidly, and it relates what is happening now to what happened before in order to identify the present event. But that reaction also has dangers, because it can be mistaken. A person can learn to take a little more time to see if something is a danger or not. It is not easy to do that but it can be done.