Ex-believers, what made you quit your religion/cult?

Learning about the world, in school and by reading humongous amounts of books when I was a kid and preteen. I eventually realised that "nah, I don't believe that." and that was that.

That's the sanitised version lol. A number of those books were by Erich von Däniken, unfortunately, and that simply "overwrote" Christianity in my young and impressionable science-fiction loving mind. Luckily I continued learning and not TOO long after I realised that was bullshit too and in the process I also actually realised why religion doesn't make sense to me.

tl;dr: HP Lovecraft made me atheist