Angry / Bitter more accurately describes those who feel let down by God and therefore actually accept the concept of deities after all. For me personally I LOVE, LOVE, LOVE the topic of religion but sometimes the religious make me a little mad

My experience was a lot like Tokyo's except the part about being in Japan

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I guess we would both also say that there was a LOT of reading. Reading the entire bible from cover to cover is the surest way to lose your religion. And don't do it more than once because the 2nd time through is when you actually do get angry

. You just feel lied to. As a adult you see the actions of both the deity and the people for what they are. You also start to hear the voices of those religious zealots and politicians who were the actual writers trying to shape the minds of the world. Then you discover all of the redactions and start to wonder "what were they trying to hide / add to the story?"
If you move your questions and reading to outside of the bible to history and also study other religions the whole thing just starts to unravel before your eyes. Logically, emotionally, morally, ethically, etc., etc.
I used to think they were clever but now I'm thinking more that people were just struggling and not very well educated thereby allowing those politicians to take advantage of them. Not that they couldn't read / interpret for themselves but uneducated because only a very few were even allowed to have a copy of the bible. Until the priesthood and the king had a proper system in place to "interpret" to important parts reading the bible was dangerous without the aid of clergy. So much like exactly what's going on today. The majority would post a comment under the bible that says
tl/dr
One thing I wish religious people understood it that it is also saddening to find out something you believed in so strong you can now only consider a fairy tale. I tried so hard in the denial phase to hold on to some of the faith I knew for so many years but it eventually became just silly. Once I got over that I had to work on my entire world view.
I really want to add a quote that sums up my views today but as a former Christian I know it sounds too harsh. I'll just say I feel sorry for the character called "God" because for as much as "he" gets credit for things humans do, "he" gets blame for just as much. Kind of unfair but since I don't believe in deities I think he'll be okay.