Most people do not like changes. Changes cause uncertainty, fear and disturbance.
Certainly not all changes in a person's life are positive. Loss of beloved persons, undesirable changes in professional life and many other unpleasant events happen everyday. However, according to psychologists even changes that are considered to be positive developments in life (marriage, becoming a parent, moving in a new house, promotion) are experienced by many people as sources of big stress.
Isn't it contradictory that the main prerequisite of evolution, change, is causing so often negative feelings?
We are the most intelligent creatures on planet Earth. This makes us forget that we are nothing but mammals and as such we still bear deeply rooted primitive instincts. One of them is the instinct of survival. Depending on the circumstances that particular instinct is causing two reactions: either fight or fly.