There are many survival responses in addition to Fight or Flight, which can get activated when under stress. Fight and Flight come from the idea that our ancient ancestors had to either fight off the bear or run from the bear.
But in our modern world, the dangers we face usually come from other people and our own mistaken beliefs about ourselves, others and the world around us.
The next most talked about survival response is Freeze, which many young children learn to do as they often don't have the option of running or fighting. However, when we are forced to Freeze and are stuck in a dangerous and unsafe situation, this can lead to various physical and mental health problems. It can also lead to anger.
Fight or Flight is about action. The physiological changes in our body caused by the stress response prepare us to take action. Running or fighting releases the tension our body is under when the stress response is triggered. When that tension isn't removed, it builds to a point where it can no longer be contained and comes out in anger.
Just so you know, the other 'Fs' are Fawn, Flood, Fatigue, Flop, Feed, and Fornicate. Fawn is when we find safety is catering to the needs of our abuser, sucking up to stay on their good side. Flood is when our emotions overwhelm us, and we start crying and can't stop. When a person is overwhelmed with emotions others are hesitant to approach them. The flooding of emotions creates a barrier. Fatigue is our body's way of keeping us safe by preventing us from doing anything due to an overall lack of energy. Flop is like Freeze; expect muscles go loose or limp. Feed is essentially eating to deal with stress; when we overeat or undereat, we go numb. Finally, Fornicate, using intercourse as a way to stave off or relieve stress.