I have a fascination with deconversion stories. I was never a believer myself, and I have no idea if I would have had the honesty and bravery to overcome such emotionally manipulative indoctrination as religions use. I've read or heard scores, possibly hundreds of deconversion stories.
While the stories I read were not a properly selected sample for any kind of scientific study, I have noticed certain patterns.
Normally, the process of overcoming indoctrination can take months, years, or even decades to unfold. Admitting that you were wrong about something for your whole life can't be easy, and for most, the process involves a lot of introspection and a lot of study, but very rarely instant deconversions happen.
If it can be said that the overall sample is not a representative sample, that goes double for the number of instant deconversion stories I've encountered as the sample size is extremely small.
Richard Feynman
The most famous one would be American physicist Richard Feynman. The story of his deconversion is in one of his autobiographies, but forgive me for not remembering which one. It's been decades since I read it.
As a child, one of the stories in the Jewish holy scripture bothered him. One of the characters' stories continued after his last contact with other humans, then the character died alone. I don't remember the name of the character, but I'm pretty sure it wasn't Moses.
Anyway, young Richard was annoyed by this. Of course, the story should have ended with the character's last contact with other human beings, otherwise, how could the story have been written down in scripture?
Curious, he asked a rabbi about this. I don't recall what the answer was, but the answer was so bad that young Richard became enraged and instantly deconverted on the spot. He never again believed in the religious teachings of Judaism as long as he lived.
To the extent that we can say there are patterns (and I probably shouldn't), it always seems to happen to very intelligent theists, and the instant deconversion is never caused by a good argument from an atheist, but by a bad argument from a fellow theist.
Theists imagine that deconversion must involve anger or sadness, but for most, deconversion is a lengthy intellectual endeavor. If there is sadness or rage, that usually comes when former friends and family cut off all contact due to the deconversion. The deconverion itself can involve any emotion, combination of emotion, or no emotion. Mostly it's an intellectual labor. But instant deconversion is different. Instant deconversion always seems to involve rage at an incredibly bad argument from their own side (a fellow theist). And no, the rage is not directed at the theists' imaginary friends, but at the person making the bad argument.
Aron Ra
Aron is an Internet atheist personality famous for his work on TalkOrigins.org and YouTube.
Like a normal deconversion, Aron experimented with other forms of theism on his path away from the religion of his birth (Mormonism). He experimented with paganism, witchcraft, and a number of other things. Unlike most deconversions, he then took a hard turn back towards a rigid variety of theism and became a born again Christian.
He was very excited about the born-again experience, then asked the friend who steered him into the born-again experience how he could possibly know if the things he was feeling were real or just something he talked himself into. That was when his friend gave him the famous Fake It Until You Make it argument (which I think originated in the essay people get Pascal's wager from). Aron became enraged by the argument and instantly deconverted. Again, we see the same pattern: an intelligent person enraged by a bad argument from a fellow theist.
Sal
I hope Sal will forgive me, but I am certain I would misspell his last name if I tried. I only ever heard about him from a round-table discussion between the Secular Latino Alliance and Aron Ra.
Sal's wife actually deconverted first. He tried to bring her back to Christianity, and he asked her to watch the Bill Nye-Ken Ham debate. Sal was certain that Ken Ham was a serious intellectual, and that his compelling, fact-based arguments would win his wife back to Christianity. Instead, Sal became so enraged at the bad answer Ham gave to the "What, if anything, would ever change your mind" question that he instantly deconverted.
Conclusion
I've always found the use of bad arguments a curious thing among theists. I was always told that when you find out an argument is bad, stop using it because it will undermine your position. But I've noticed that Christians and Muslims will continue using an argument even after someone has demonstrated to them that a given argument does not actually support their conclusion.
I assume that Christians and Muslims continue using arguments even after they find out the arguments are bad because they think all atheists are morons and that they can still convince atheists with arguments they know to be bad, but the truth is bad arguments don't win people from the other side to your side, bad argument repel people from your own side.