But the second great reality that the Bible teaches us about is sin. If the purpose of our existence is to know and enjoy and reflect the glory of God as our highest value, then sin is our failure to do that. All of us have sinned. There is no exception. And sin mainly has to do with our relationship to God, not man.
Sin hurts people.
But that's not the main reason it is evil. The main reason is that God is worthy of our trust and obedience and worship and our joy, but we treat him like a raincoat, leaving him in the closet forgotten until it rains hard enough outside. God is not a raincoat for bad days. He is the Giver of the sunlight and the Creator of the clouds and the Sustainer of every breath you take and the Judge of all the living and the dead. Therefore, our neglect of God is a great evil and we are guilty of sin in his presence.