I seem to be somewhat of an oddball in this respect (though I think there were a few here that went through a similar process). I've been atheist in all but name for probably about 12 years (all my adult life). Of course I did lip service to god, sometimes I prayed but it was always more of "cover your bases" kind of way because there was always that little bit of doubt that the JWs might be right. All the while I spent much time musing on the impact of atheism on morals and on the meaning of life and the conclusion I always came to was that religion was unneccesary. But always there was that tiny bit of doubt. When I found jwfacts, and the outright lies in the creation book, it was like flicking a lightswitch. In that moment I became a full-fledged atheist and a weight was lifted from my shoulders (but a heavier one replaced it since I'm not stuck in for my wife's sake).
This seems to be a pretty common tragectory that people take upon leaving their religion - once you start thinking about things critically it's a difficult habit to lose. This appears to be especially the case among former JWs. So much of the JW religion is about mocking other religions and pointing out their flaws that it makes it very difficult to then go and join up one of those religions without being able to see them for what they are.