For me the awakening point started when I read Crisis of Conscience. That was over a year ago and started me actually "thinking" (I had not been going to meetings at the time so I was much more receptive to that book at the time)
Then I went back and got DF'd and that hurt, and so I started looking around and finally doing some real research on "my" religion and found jwfacts.com and that really started opening up my eyes.
At this point the "One Thing" for me is the false prophecy. Duet. 18:20-22 really drove it home for me. The WTS has indeed thrown out many many false "prophecies" in the past, in fact starting from Russell. None of them have come true. The end of those verses says "The prophet has spoken it presumptuously; you shall not be afraid of him." And guess what, that was it for me, the defining "I'm awake" moment.
From there I continued and continue to research and the more I learn the more baffled I have become that I fell for it all for so long. There are myriad things that prove not only the WTS is wrong but all religion in general and now I'm even questioning the belief in God at all. I no longer believe the Bible and honestly I'm pretty sure there might be a "first cause" but as for a God who cares about us or what we do, think, or how we worship? No. I don't believe any of that anymore.