In the King James Bible you will find the following passage in the book of Genesis: "And God said, Let us make man in our image, after our likeness." Many modern thinkers know the opposite to be true. It was humans who created god in our image. The god of the Holy Bible is thought to have created the universe and earth, is omnipotent and omniscient, highly involved in human affairs, and interacts with his creation; performing miracles, causing floods that wipe out life, and even speaking to humans. If there is or ever was a god, it is impossible that it could be the Christian god. Let us go back to the beginning when man invented the first gods.
It is clear that the first gods known to humans were an invention. In ancient times there was an ignorance of the workings of the natural world. Facts that are now common knowledge like the fact that the sun is a ball of burning gases were completely unknown. Humans in those times were just as curious as we are now and they wanted an explanation. They made up their own explanations by inventing gods. One of the first deities worshipped was the sun. It is easy to see why. The sun brings light and warmth. They believed it to be the giver of life. Many of the gods throughout history were sun gods like Horus who was worshipped by the ancient Egyptians. The gods of ancient times looked like humans and even behaved like humans. Gods had husbands and wives, and children. They also had their share of issues and problems. The gods of the ancient world resembled humans in every way except they had very important jobs like raising the sun in the sky each day or controlling the tide. There is no place for these gods in today's world because science has explained how these natural events occur.
Even Christians have to admit that these gods were invented by the human mind. One of the tenants of Christianity is that there is only one god. By believing in Christianity, one inherently believes that the thousands of other gods that have been worshipped throughout history have been invented by humans. If humans got it wrong so many times before, why believe in this particular god? The only evidence for the existence of the Christian god is The Holy Bible. This book which is supposedly the word of a god, who is perfect and infallible, is filled with atrocities, absurdities, and contradictions. It wouldn't be a surprise to find these things in a book that was written by men but the idea that a perfect god has written this book is pure stupidity.
There are those who decide to remain undecided or "agnostic" about this issue, claiming that to be an atheist requires faith. It requires no more faith to say god does not exist than it does for you to confidently tell a child that the boogeyman is not real. If you are not agnostic about the boogeyman, unicorns, fairies, leprechauns and the flying spaghetti monster, why claim that you are agnostic about god? We have just as much evidence for any of these beings as we do for god which is none. The boogeyman could have made the universe out of the horn of a silver unicorn and we wouldn't know. If we apply your reasoning we should be agnostic about that as well. Christopher Hitchins said "What can be asserted without evidence can be dismissed without evidence." I find his reasoning to be more practical.
It is my opinion that god is nothing but an invention of the human mind. God is an easy answer to questions we don't know the real answer to. The first gods controlled the weather, the stars, and the rate at which the crops grew. We now have a basic understanding of these natural processes. God is now used to fill in the current gaps that science hasn't yet covered such as the origin of the universe. Eventually, the gods people are worshipping today will no longer serve a purpose and they will fall into the ranks of Zeus and Horus. The citizens of the future will look back and laugh that people put so much time into debating the existence of an invisible sky man who listens to your thoughts.