Past and Present are One

Why do we sometimes have massive emotional reactions to apparently insignificant events?
Why do we react "childishly" to a small reproach, disagreement or disappointment?
It is because the brain makes no distinction between past and present. Whatever memory is triggered from the past, becomes present time behaviour and because of the brains layered memory it all happens simultaneously.
Every painful or fearful event is etched in our memory neurons and every time we have a similar experience all the layers of memory are triggered and we respond on the basis of the sum total of these memories. Within seconds you can see it transform facial expression, body posture, tone of voice and attitude.
The truth is that we need not be at the mercy of these past, undesirable memories; our conscious mind has the power to direct how we think and react in the present. It also has the power to suppress what we do not want to think about. By denying what we do not wish to see, we suppress it and decide what we choose to remember on the conscious level. But whatever we suppress lives on in the subconscious, every bit as real as conscious memory.
So whether it is real or imagined, the brain and body respond the same way and we re-experience what we did and how we felt in the past.