It's a long story. Basically, "generation" always bothered me. But I didn't peek behind the curtain.
Double standards finally got to me. A friend was involved in looking at pornography and masturbation and was disfellowshipped. I knew that they generally said that elders involved could say it happened only a few times and they stopped, then they can even remain elders and nobody is the wiser.
On top of that, I was asked to go down to Hurricane Katrina Relief (months after the storm) and then the Regional Building Committee (RBC) cancelled me at the last minute, saying they had "no more room on the bus unless I was a plumber, electrician, or carpenter." They would not let me drive down and join saying "We don't do it that way, all things according to order and procedure." Then later, I find out that the same bus held the wife of the RBC chairman and his little kids, and they did no plumbing, electrical work, carpentry. They had a huge picnic on the last day instead of doing more work that day. So much bullshit. I was going to break my back and help people.
So finally, I said that research for JW talks made me pretty much an expert at "googling" everything- even without Google before it existed. So I said I would google "Jehovah's Witnesses" and figure out what's wrong and take a look at every single link no matter how I feel about it. That was the beginning of the end for me.