The following story is without a doubt one of the major causes of my more serious doubting. Like many of the doubts I've mentioned, this goes back to my days as a missionary.
My companion and I were working on reactivating a guy in his late 20s. The man had some serious hygiene problems but he had quite a brain. He and his father (then diseased) had converted from the Jehovah's Witnesses about a decade earlier only to both go inactive a few years later. My companion and I were thrilled to be in contact with him because (1) we didn't have many solid contacts, (2) we wanted to get more Priesthood holders into the branch, and (3) we fucking hated Jehovah's witnesses and didn't like that this guy had (supposedly) returned to them.
I had never seen the kind of enthusiasm this guy had ever before. He was all about Joseph Smith and the Restoration. He loved all the visions, all the revelations, all the visitations - everything. He wanted to hear it all. He had studied a number of the American religions that had sprung up in the early 19th Century and apparently had found Mormonism extremely convincing.
We would come to us having read sections of the Doctrine & Covenants and testifying of their truthfulness. The man was on fire with the spirit. Hungry for the Restored Gospel. Eager to share the confirmations of the spirit.
In fact, he was the most spiritually sensitive person I had ever taught by far. One day he told us about a dream he had in which his diseased father appeared to him in a dream bearing testimony of the Church. In the same dream he even heard the voice of Joseph Smith confirming that he would once again be with his father in the Celestial Kingdom.
It was amazing! Visions! The voice of the Prophet! I was so excited for him, not to mention jealous! Holy shit, it's all real! Our guy is living it the way it was meant to be! My companion and I were sure he was going to be leading the local church within a decade. Shit, this dude was going to be an area authority by the time he was 45! He was going to lead the church in that country with the power of the Spirit unlike anyone before him! Every meeting with him was magical. Our meetings with him always ended on a high note.
We loved this guy and loved what he was going to do for the Church, so when he called us in desperation one day asking for some financial help we were ready to assist. We weren't too thrilled that he had asked us for money, though he had promised to pay us back the next week, but my companion and I talked it over and prayed about it and eventually came up with $120 that we compassionately handed over.
As you likely suspect, we didn't hear from him for a long time, and when we did hear from him a month later he was telling us that he had up and gone to the UK for some English course. We knew he had scammed us and we knew he was lying to us. We knew that he had always been lying to us about everything. That for whatever reason he had been trying to wrangle as many copies of the Doctrine & Covenants from us as possible. Then he wanted our money.
We could have killed him, but we kept that to ourselves. Once we finally managed to convince him to meet us again we called him out on his bluff. He, of course, got upset and a shouting match ensued, after which he stormed out of the church. Our problems with him continued for a time. At one point he threatened to call the police on us because we still had the Discman he had left in the church the day we had our big fight. It wasn't a pretty scenario.
The most troubling thing about the whole situation was that my companion and I had felt the Spirit the strongest we had ever felt it before while listening to this guy's stories. Considering the fact that he had made everything up, what was it that we had felt? Why had God allow us, his humble and dedicated servants to be so badly conned? What did this whole experience mean with regards to the other experiences I had with the confirmations of the Spirit? And what did it mean with regards to God's personal investment in our work (his work)?
It's not that I had never doubted the power of the Spirit to communicate before, but now things had somehow become much more serious and real. Could I trust God? Was the Spirit a load of bullshit, nothing more than happy feelings of confirmation bias?