For me there were a lot of little things over the years that gradually added up to a big, hollow pit of fear in my gut that wouldn't go away. After 1975 came and went, I dully realized that something was wrong. I kept having visions of myself 25-30 years later, still working in a shitty job and hating my life. My father-in-law -- never a JW -- eventually convinced me to go to college, which I did in 1978. Over the next four years I was mostly inactive due to the work load, but kept telling myself I'd get back into the swing of things JW when I finished. During that time I had to do some research using JW literature on creation and Noah's Flood as source references. I discovered that a lot of the Society's references were bogus, which just reinforced my vaguely ill feelings about the Witnesses.
After college I got a good job, and my wife and I moved to a new state where we got fully back into JW life. But I still kept finding out things that made me think that the Society was full of crap about some things, like creation and the Flood. In late 1982 they put a really stupid article in Awake! that vaguely argued that animals eat each other because of Adam's sin, which made me realize that these guys were just winging it and God had little if anything to do with what they wrote.
A year later came a defining moment. I was in a car with three other JW men one rainy Saturday morning, doing the usual not-at-homes with a car group. Every 15 minutes two of us would get out and verify that another not-at-home was still not at home. At the end of about two hours I was sitting there being irritated at the wasted time, when it occurred to me that I didn't have to be there if I didn't want and so I decided not to be there anymore. I decided not to attend meetings any more. Later my wife begged me to go to the occasional Sunday meeting. So at that point I was fully inactive.
Over the next few years I was nothing but irritated whenever I went to a Sunday meeting or an assembly. I did some library research and some looking into some of the Society's more stupid teachings, but it was hit or miss because I didn't want to start something I thought I might be afraid of finishing. Finally in late 1990 I started doing some intense research. I found that the Society had told massive lies in some of its publications, especially in the 1985 Creation book, and that made me extremely angry. But I kept it inside. Later I bought a small book critical of JWs, and that gave me an introduction to people who had written critically about JW history, the 1914 doctrine, and of course Raymond Franz's experiences.
By mid-1993 I complained bitterly to my parents about the lack of response I was getting from all quarters among the Witnesses, from them to local elders to the Society itself. So they used a bit of personal influence and convinced GB member Albert Schroeder to talk to me on the phone. We talked one Sunday afternoon for about 2 1/2 hours. I went easy on him, but hit him with some things he couldn't answer. He reluctantly agree to review some research material I would send him. By the next summer he had not gotten back to me, and so in August I called him and told him that I would be in New York on business in September and asked him to meet with me. He refused but said I could call him on a Saturday morning in his office when it wouldn't be busy. I did, and asked him why he hadn't fulfilled his promise. He hemmed and hawed. At one point I asked him why the JWs are an exception to Jesus' words of warning in Luke 21:8 about not following anyone who predicts the end. He said, "It can't apply to us because we're God's people!" Finally I cornered him on whether he was ever going to fulfill his promise to respond to the material I sent him. He said that he would not, and I asked him why he was reneging on his word. He said that they at Bethel had better things to do than answer the questions I had given him. At that moment it hit me like a ton of bricks: these people are not interested in their "flock" but only in mechanically doing their "preaching work". At that point I knew with absolute certainty that there is little of redeeming value about the Watchtower Society and I knew that there was no point in trying to get truthful answers from determined liars. I had no more little twinges of "even after all my research, maybe they're still right". I finally and reluctanctly realized that Watchtower leaders are incorrigibly evil.