Humanity has not changed at its core in thousands of years. It's what humanity uses to highlight and shine a light on the core of what humanity is really like that changes. Our technology changes and advances. Our language changes. Our cultures change to some degree. Even our religions change. Our currencies change. But humanity has not changed. Individual humans do change and some even improve. Even small groups have the ability to change and improve. Don't put your faith in humanity as a whole though - you'll be disappointed and frustrated. Have faith in God, in individuals that you have come to know and trust, in the things that are inevitable in life, etc.