Even though the fight or flight response is automatic, it isn't always accurate. In fact most of the time when the fight or flight response is triggered it is a false alarm - there is no threat to survival. The part of the brain the initiates the automatic part of the fight or flight response, the amygdala, can't distinguish between a real threat and a perceived threat.
The important thing to take away is that the fight or flight response is an automatic response..wondefull post @abiye