It is the key factor which has enabled all life to grow and develop at the speed it has. Physically, every cell in our body is replaced every seven years. Research is now revealing that many of our physical ailments, diseases, and trauma are caused by controllable factors in our environment. Modern science is revealing some of our most basic mental preconceptions as untrue. Brain cells do continue to grow throughout our lives if they are appropriately nourished.
Maturity is a state few people attain.
Many of our beliefs about the aging process are now being shown to be inaccurate as we discover species in the animal kingdoms which have a totally different physiology. Quantum physics is revealing that our universe is a far more fluid and fickle construction than any of us would care to imagine. At those quantum levels of subtlety, our expectations and actions determine the outcome - not a fixed 'rule' of physics. Thoughts become self-fulfilling prophecies. In addition, we selectively view the situation so that it fits with our preconceived views, our paradigms.