Man made God and not the other way around
It is self-evident that man created God. In the days of Ancient Greece, religion had a completely different outlook with a whole system headed by Zeus at the Olympus where an array of deities, Gods and Semi-Gods constantly interfered in the lives of Man.
To explain Death, Man created the concept of Heaven and Hell. In Ancient Greece, Hell was ruled by a God. There was a constant struggle between deities, Gods and Semi-Gods, a constant quest for power that very much reflected the everyday world. Judaism and its branches called Christianity and Islam - both born out of the Judaism - adopted a system in which there was only one God, the Creator, and got into trouble trying to explain the origins of Man.
If Adam was created by God and later on Eve was created taking a rib out of Adam, nobody could logically explain where the descendants of Cain came from. Were there other women and men not related to Adam, Eve and Cain around? Where do they came from? If there weren't any other women and men not related to Adam and Eve around, did Adam and Eve also had daughters? If they had daughters, then the Human Race was born ouf of an endless number of incestuous relationships and genetic mutations that would have led to different ethnic groups.
To sum up: the concepts accepted by Judaism, Christianity and Islam are the consequences of irrationality, an irrationality that could only be maintained by fear and by a power struggle. Religion is in fact Political Power and for centuries all those who dared to challenge the imposed view suffered terrible consequences.
The so called perfect system presumably created by God is not perfect in any way, shape or form. Since Man appeared on Earth he has been hunted or being a hunter. We only survives thanks to murder and destruction. Millions upon millions of animals that are supposed to be God's Creation have been destroyed, are destroyed and will be destroyed on a daily basis just to keep Man alive. Man also kills for the sake of entertainment and to feed other animals that it is said that Man wants to protect.
The Bible, for example, says 'Thou shall not kill'. Well, incidentally, killing is what has kept Humanity alive. We might blame an asteroid for the disappearance of the dinosaurs but the level of destruction caused by Man has led quite a few species towards extinction.
Every day, we kill on an industrial basis. Species living in the waters and on the ground are being systematically destroyed, natural habitats are being destroyed and this is the consequence of the actions of Man and Man is faced with a stark choice: if we don't kill, we starve to death. So the statements about 'Thou shall not kill' is purely and simply bollocks. We kill other Human Beings and we destroy Animals by the millions of millions on a daily basis. If you believe in God then the direct conclusion is that God created a monstrosity, an endless chain of pain and barbaric actions.