As human beings, we, by the definition of our very natures, can never be perfect. This means that as long as we are alive and kicking, we can be improving ourselves. No matter our age, if we always have a project to which we can apply ourselves, then we will wake up every day with an objective, something productive to get done. This allows us to go to bed at night in the peaceful knowledge that we have done some good, gained some achievement, however small.
