So God created mankind in his own image, in the image of God he created them; male and female he created them. God blessed them; and God said to them, “Be fruitful and multiply, and fill the earth, and subdue it (Genesis 1:27-28). As image bearers of God humans have an obligation to serve him. Whether you were raised in a good home or a bad one, it is important to understand you bear the image of God. His stamp is on his creature. Human: Made by God!
When you understand that you were made by God, you understand why He is concerned with us obeying His will. He owns us. He created us for His enjoyment. Not only that, but God gave us His eternal breath. It is the reason we do not cease to exist, even after death. It is the reason He died for us. We are His creatures. His breathe gives us life.
How much more do men or women fancy their creations, a painting, a song, an organization, a play, etc. Putting themselves into the pieces they create and what response would they have if someone ruined it? Some, have killed men for less. So when God gives you an opportunity to receive a life of peace, a destination of heaven, what do you do? Do you take it or do you reject God who created you in His image? How do you think the God who gave you feelings, would feel?
How evil is it to reject God? It is very evil. The One who gave you life.