As a simple matter of human nature, each of us believes as we do because someone taught us that way, and then we learned from others and melded their ideas into our own psyche to become our current belief. For some of us, that might have started out as being raised into a given religion by your parents. This is the typical way it starts. For others, this might mean a change of religion. Say, for example, being raised as a Catholic but then changing to some Protestant denomination - or vice versa.
Then there are those of us who went through an intensely emotional period that forced us to totally rethink, and in some cases, deeply analyze our beliefs. I personally fall into this category. Some years ago I lost my mother to Alzheimer's Disease. During that time I was still Methodist and a believer. I turned to the Bible seeking comfort, solace, understanding, and in general, some easing of the terrible pain of seeing my mother go through the terrible progression of that disease all the way to stage IV (alive but generally unresponsive, vegetative, but technically not yet brain-dead). That is when you ask questions that start with "WHY."
All of the questions I asked led me to the same answer - read the Bible to find the reason. But the more I read, the less I trusted it. All of the answers people gave me led to the same conclusion. It is that all answers of the general form "God works in mysterious ways" are equivalent to saying, "We don't know either." Answers like "We are not meant to know God's will" are essentially useless because they offer no comfort.
If you look in Ecclesiastes or Psalms, you will find passages that tell you that "Dead is dead forever." OK, more eloquently phrased, but basically you are born, you live, you die; once dead, you have no thought, no memory, end of story. That was one of the few parts that made any sense whatever.
That is when I looked at the Bible itself as a reference for God - and realized that it is nothing but a bunch of stories who thought there was this supernatural being who had something to do with reality, so they did things as though God mattered. OK, great - but where's the proof? When I asked that question, all of the really showy proofs turn out to have no historical corroboration from contemporary mundane authors. There are no relics that prove anything other than that certain cities existed historically.
The more I studied the subject, the more I realized that these Biblical stories were in the same exact category as Aesop's Fables or Grimm's Fairy Tales. They are stories used to preserve traditions by allegory. They are stories used to amuse, amaze, and sometimes to frighten small children eager for diversion in a primitive culture that had no radio, TV, CDs, DVDs, iPads, PCs or consoles with video games. These were stories for kids who gathered around a hearth or campfire to hear the tribal/village storyteller recite the stories he learned by rote as an apprentice to the previous storyteller.
Put in that context, the Biblical stories provide insights to an older culture and they describe a type of morality based on fear of the supernatural. But the price of religion based on fear is a creeping paranoia, that feeling that someone is looking over your shoulder and judging you. There is also that strange method of trying to avoid other "sins" of various types - giving praise to God for what YOU do and seeking God's guidance. But waiting for an absentee deity is like waiting for Godot - He never shows up.
My own pain was eventually resolved by resolving the cognitive dissonance of having a belief ingrained during childhood that turned out to be based on NO evidence, NO logic, and NO testable phenomena. I had to face the pain of having been lied to by my parents. The anger of "How DARE they tell me such lies?" was eventually assuaged by the fact that they were merely repeating the lies someone else told them. Then came forgiveness for being frail and human.
Somewhere during that terrible period I became a budding atheist. My mother's death took away the continuous pain of seeing her degenerate from a lively, happy, loving woman to a lump of unresponsive but not yet dead flesh. But the seed of thought had been planted. Now, I realize that part of the problem is that we are taught very strongly in our youth. When we confront our teachings, the love for those who taught us makes us unreceptive to the idea that they lied to us, or at least spread a lie that had been taught to them.
Just one man's story of a journey to a different kind of enlightenment, with the closing thought that it took a powerful situation to enable me to break through powerful childhood conditioning. This is why when someone is unable to break out of the vise-grip of religion that I can forgive them, for it is clear that they have not yet had their own personal moment of anguish that led to that self-examination.