I was born in, and over the years came in to contact with a number of Apostates and religious people prepared to show the errors of JW Theology, I had long conversations with Vicars, and once a Bishop, none of these had the desired affect, I was left still a faithful JW.
Then one day I was simply looking around the K.H at all the folks there , chatting away to each other after the meeting, and the thought came in to my head " What if this is all wrong ? not true ? all of us here would be following the wrong religion!".
That was the first big crack in my "Spiritual Armour" I guess, just allowing that thought to take shape, and stay with me. Eventually I left because on my own I came to the conclusion that the 1914 teaching was NOT in the Bible.
It was only after leaving that I was helped by XJW's, that i found others who saw through 1914 and much more !
The doubt was born in the Kingdom Hall for sure with me !