The brain is wired to make instant decisions, based on comparing something that is happening now with what you remember happening in the past, in order to decide whether it is a threat. So you have a hard time not reacting now the same way you did in the past -- you have a hard time slowing your need for an instant reaction so that you can more thoughtfully examine if now is different from the past. You tend to see the same thing as you did before.

My thoughts, anyway...