All of us have failed to glorify God as we should
What does it mean to "fall short of the glory of God?" It means that none of us has trusted and treasured God the way we should. We have not been satisfied with his greatness and walked in his ways. We have sought our satisfaction in other things, and treated them as more valuable than God, which is the essence of idolatry (Romans 1:21-23). Since sin came into the world we have all been deeply resistant to having God as our all-satisfying treasure (Ephesians 2:3). This is an appalling offense to the greatness of God (Jeremiah 2:12-13).