When we are born into this world, everything is about us. We cannot feed nor even care for ourselves, so others must do so. Some people never grow out of the egotism that results.
As they grow, children learn to do more. However, they are utterly unprepared for the world and require constant supervision. There are adults who need someone looking over their shoulder to be productive.
Adolescence brings about many changes, for now a human being is physically able to take care of themselves. Still, they are afflicted with a bad case of idealism since they have never had to make real decisions. This naivety persists for many, and they do not progress to become responsible individuals.
Reaching adulthood, humans now think they know everything. Experience teaches them the error of their ways. However, there are those out there who will never learn.
Once experience has its way, people become set in their ways. They have forgotten adaptation is necessary for survival. Many will perish, refusing to change.
Life is a cycle of good and bad: mistakes made and lessons learned. Those who know when to change and when to stand firm will progress and thrive. Others complain they were never given a chance, when they squandered every chance they had.