I don't think there was a final WTF moment. I don't think I was ever really an organization sort of witness. It was more to do with God. I had no aspirations to do anything at the hall and generally disliked the meetings and field service although I pioneered.
When I was growing up there was always a lot of conversation in house regarding the truth and a couple of times I remember my father going on about things that had changed, one being the baptism.
I never intended to leave and thought that things would be explained in time. A Watchtower article had made me see things differently and I my autopilot adjusted my life for me meaning less meeting attendance and no field service and I had to discuss my feelings with my friends that brought the elders round.
Since I left I was totally surprised once talking to an elder about Christ and John 1. and more recently I was shocked when I spoke to an elder and we couldn't agree on basic things that I had understood as a witness. So maybe that was my final moment.
I kind of figured it out, the reasons how and why I left, since I've been posting here. Or at least made more sense of it.