It has an important role in preservation of the individual. If there is any sense of physical threat, the brain stem will activate the fight or flight mechanism to protect the individual. The significance of this is that it overrides all higher brain function to accomplish its task. In reptiles, fight or flight is simple and to our knowledge, without emotion. Fighting or fleeing, unlike in humans, isn't connect to feelings.
Feelings come from a very structurally complex area of the brain known as the limbic system.
This portion of the brain is significantly higher in evolutionary terms and the part we share with other mammals. The limbic system's major functions are cognitive and emotional. It controls your feelings, experiences and memory. Memory affects the ability to learn, which is a neocortical function. The limbic system is a vital part of the brain and important to human preservation.