I don't want to derail the thread, but on the other hand it's rare that a thread sticks to the subject of the OP for more than a few pages.
There wasn't one single trigger or incident that caused me to lose faith. It was a long and very painful process. But there were a few things that contributed more to it than others. For example when I decided to stop praying, to see whether or not prayer had any effect. As far as I could tell, it didn't (other than the feeling of comfort you can get in "pouring out your heart to God" etc). I didn't see anything happening in my life or in the lives of those around me that could reasonably be said to be the result of prayer, yet we would constantly talk about them as if they were. Like if someone's tumor turned out to be benign, or they got a job or whatever. I stopped praying, and didn't notice any difference at all. That doesn't mean nobody's prayers are working, but it does mean mine weren't, even though I thought I had seen it work my whole life. It turned out to be confirmation bias.
What I learned was that 90% of life is just normal routine, no highs or lows - just the normal routine of getting up, having a shower, breakfast, then off to work, come home, stroke the cats, have dinner, watch TV, then off to bed. Day after day.
it's a bit like an airline pilot - mainly routine, but 30 seconds of blind panic!
I can say after 52 years as a Christian, I have not seen a particular answer to prayer, and I have prayed almost without ceasing over that time. I prayed for reconciliation when separated from my first wife, but that didn't happen. I learned that prayer does not change the will of another person who is free to make their own choices. I also have prayed for people with cancer, and not seen them healed.
So, I stopped asking God for stuff, treating Him like a vending machine. My prayer life has been discussions, sharing thoughts, asking for wisdom, help in making decisions. Just last night I told the Lord that my wife would be much happier being closer to our daughter who lives in another city, and it would be good if we moved there. But I can't persuade her because she may feel obligated to comply with my wishes. I told the Lord that the idea had to come from her, and then I would know that it was right to move house to that other city. At our age (me 71, and my wife 69) the logistics of moving house are going to be huge, and so there are a lot of ducks to get in a row for that to happen. If it happens it happens, if not, well, it won't.
There are two Scriptures that come to mind:
"Those who are led by the Spirit of God are the sons of God." What this means to me is that we are being led all the time, and most of the time we don't realise it. It is only when we look back over say the last couple of years that we see some sort of pattern of events what have led us up to this point. Proverbs say that a man may plan his way, but the Lord directs his steps. I think the man is never conscious of being directed.
The other Scripture was that Paul said he was content in whatever circumstances he found himself in, whether positive or negative (my paraphrase).
A good preacher once said that 99% of us will never be famous, never have a great ministry, but will be a small fish in a big pond somewhere just getting on life doing what they can to fellowship with the people around them.
I guess the issue is one of expectation - what we expect from God. I expect nothing. Jesus said that blessed are those who have seen, but also blessed are those who have not seen. I am one who has not seen anything unusual or spectacular but I am assured that I am blessed, nevertheless.
I hope that is helpful in some way.