Now there is a lot of semantics involved here, but atheism, as I understand it, is about rejecting someone else's beliefs, one that they did not create and refuse to accept as true or valid. That is not a belief, but a rejection of someone else's. Usually once you reject your religion of birth it becomes easy to reject other religions and their God, or deities, because many of them make claims that require a leap of faith, which an atheist has probably already rejected by then. An atheist does not claim to know with certainty that any Gods exists, just with confidence that certain Gods do not.
Now I am not an atheist. I have been though, and may be considered one by others. Again, this depends on semantics. It can only be considered a belief if you equate the definition of belief with having an opinion, which is counter productive because a person with religious convictions hardly feels that their belief is a matter of opinion. They often take their moral codes, based on their belief in and conception of God, very seriously.
I do not consider myself a Christian because to be one you have to believe in a virgin conceiving a child supernaturally, people being resurrected from the dead, and a host of other things I do not believe are possible. Yes, I'm oversimplifying here. I'm just listing some of my own objections. I can understand that it could teach us lessons in metaphor, but you are expected to believe it to be literally true to be considered a believer. According to some people, I would be an atheist because I do not believe in the Christian God. My own conception of God is that if God exists, it is beyond comprehension, hasn't placed humans as the center of the universe, doesn't interfere with our affairs, but has created our universe to be wondrous as it is. I don't think not believing in God leads to despair because I think evolution has taken care of that for us. Most people feel love and the need for connecting with others, have empathy for one another, and follow social moral codes because that is what humans have done for survival since humans first evolved. That is how religion evolved in the first place. It is unique to many social animals. Of course, our brains are different and our social behavior is much more complex and that has made all the difference.
I think it is really fascinating what our brains do. Our brain to body ratio is larger than other animals and as a result we have many abilities unique to humans. The same brain that can create symphonies, great works of art, write insightful stories, discover the cure for diseases, can also come up with a whole host of different religions and concepts of worlds that do not exist except in our heads. I would say that is what sets us apart from other animals is our ability to live our lives in our heads, thereby creating our own universes and stories of our lives, to create a narration to the world around us as if it is the largest epic ever to be told. Our brains are king when it comes to imagination and creativity.
I hope to neither offend anyone or win a debate here, only to share perspectives and arrive at some truth.
