I am an atheist and a former Christian. As a former Christian I look back to what I used to believe. I wonder how I could have been no naive.
As a Christians I had very little knowledge about evolutionary biology, physics, geology, and chemistry. Yet I argued about evolution, fossils, and radioactive dating. I claimed to know problems that scientists just happen to miss when developing these thoroughly tested methods. These supposed flaws were pointed out to me by other Christians. Now I have read several books on each of these subjects and understand more than I thought I ever would. I know now that scientist have accounted for these supposed flaws.
As a Christians I vigorously denied the existence of thousands of gods claimed by other religions, but I was irritated when someone denied the existence of my God. I had an emotional attachment to my belief. My beliefs are now based on logic and reasoning and not emotional feelings.
As a Christians I felt insulted and "dehumanized" when scientists said that humans evolved from other life forms, but I had no problem with the Biblical claim that people were created from dirt. I ignored the evidence from millions of scientific tests that pointed to a different theory. Now I study these scientific findings with an open mind.
As a Christians I laughed at polytheists, but I had no problem believing in the father, son, and Holy Spirit that are separate yet the same. To me a trinity made more sense that multiple gods. Now I don't believe in any gods.
As a Christians I got upset when I heard of the violence attributed to Islam, or any other religion, but not when the bloodshed was committed by my God. I made excuses for my God. For Example: the slaughtering all the Egyptian babies in Exodus and the genocide performed in "Joshua" including women, children, animals and trees. I also claimed that my God was loving and kind.
As a Christians I thought Hindu beliefs that deify humans were just silly. I believed Greek claims about gods sleeping with women were absurd. Yet I had no problem believing that the Holy Spirit impregnated Mary, who then gave birth to a man-god who got killed, came back to life and then flew up into the sky. I realize now that the difference between these beliefs is minuscule. One is just as silly as the next.
As a Christians I was willing to spend my life looking for loopholes in the scientifically established age of the Earth, which is a few billion years, but I found nothing wrong with believing dates recorded by Bronze Age tribesmen sitting in their tents and guessing the age of the Earth.
As a Christians I believed that the entire population of this planet, with the exception of those who shared my beliefs, would spend Eternity in an infinite Hell of Suffering. And I considered my religion "tolerant" and "loving." I am free of the fear of hell now.
As a Christians I ignored the textual scholars that showed evidence that the Bible was not a reliable source. However an emotional person rolling around on the floor screaming gibberish was all the evidence I needed. I know now it was just plain nonsense.
As a Christians I thought that the double blind studies showing prayer completely ineffective were diversions from Satan. I believed the unanswered prayers were simply God saying "No." I ignored the fact that praying to any god produced the same results. I also ignored the fact that if my god was the one true god, my prayers would be answered more often than other religions which would cause a statistical anomaly that could be measured. I don't waste my time praying now.
As a Christians I actually knew little more about my religion than what I heard in church. I did not study the history of Christianity, the early church, how the bible was written, what books were left out of the bible, the mistranslations from the original Hebrew, and the atrocities committed in the name of Christianity. This knowledge was not needed to be a Christian. Studying all of these items and actually reading the entire bible helped me see the truth.
I am happy I do not believe in superstitions anymore. I believe actions are more important that beliefs.