And now for something off the regular path
I suspect that at heart, evil begins when someone utterly rejects the belief that God exists, and created the universe. A person who has made such a decision does not consider consequences of his/her acts, because he or she absolutely rejects any concept of morality. Morality is like "law" in the U.S. today: it's whatever the government says it is at that particular moment.
Such people want to be God, but without having any principles other than the ones they like. They want absolute power, but lack any higher conscience. Lacking the truth of God, they make up whatever guiding principles they like as they go. They are without truth.
My opinion, anyway.