I was born-in
I first started questioning when I was ~13 and my first question was why it seemed that JWs were generally less intelligent than "worldly" people and shouldn't it be the smarter ones that are able to find the truth? Shouldn't it be concerning that we've made the same choice that people of clearly below average intelligence have made? Obviously that wasn't enough to push me out, but it was a start. Thinking about their cult-like behaviors (independent thinking and education discouraged, shunning, etc) made me think "that's a rule I'd implement if I were to start a cult." Then the failed generation teaching combined with some basic knowledge of the failures of 1914 and 1975 was what really set me into questioning that lead to find TTATT online.
Of course the fact that I am what a JW would call an apostate has crossed my mind.
All the ones that I saw getting converted had serious problems (mental illness, addiction, recent death of a spouse or divorce, etc). This just made me doubt more because I never saw anyone joining because the doctrine was well explained and they determined it to be the truth, they were joining because they had problems and needed support.
I was always pretty strong in my faith, in a way. I thought my faith was backed by firm evidence, so I guess I didn't consider it to be faith at all. I always wanted my beliefs to be in line with evidence, I just didn't know the evidence I'd received had been filtered and manipulated. It wasn't until I knew TTATT that I was looking for a way out. Up until that point, I was mostly looking for a way to silence my doubts so that I could stay a JW in good conscience.
As a kid I was the holier-than-thou type because I had a penchant for memorizing doctrine and explaining it. I could beat most adults at that game by the time I was a teenager. Through college I started to become more moderate (the more I learned in school the more I realized I didn't really know anything) and then after getting married and moving to a new congregation where I knew no one I became "spiritually weak" only getting the minimum in service and missing the occasional meeting. I'd started to see that JW stuff really didn't benefit me in any way and I had a lot of new responsibilities that I was better off attending to vs going to meetings or wasting my time walking up and down the street trying to recruit people into something I wasn't sure about myself.