Basically, for me it was a combination of things.
Feeling that life was unfair to me even though I was a perfect JW was the beginning. The JW way of life is strict beyond belief and I had felt embarassed inside because of practicing it.
The next part was the actual information. I watched a lot of Propaganda Techniques' (a YouTube channel about the Watchtower) channel and I don't know if I would have stayed out of the tower without that information.