Your response to stress is the result of physiology, genetics and environment. Stress is a result of the flight fight response. The brain recognises a threat, the adrenal gland produces chemicals that affect changes in the brain and bodies functioning. The factors that cause variation in stress responses would be what the brain identifies as stress and the capacity of the adrenal gland to function. A person that lives in a fairly isolated location, the country say, may have very few challenges in life may have a calm and easy going personality but when faced with a crisis or a busier environment they may find themselves unable to cope. The high tempered and aggressive personality might have developed in response to many changes and challenges
