Found on Twitter: https://mobile.twitter.com/paulg/status/1172767548363935744
1. This WaitButWhy article on artificial superintelligence started my journey down the rabbit hole of AI alignment and actually, as a matter of fact, changed the course of my life
2. Runner-up: Meditations on Moloch - unsurprising choice, but it did have a profound impact on my worldview
The criteria for choosing your answer should be the impact the thing you read had on your life, not whether you agree with it, learned from it or would recommend it to others, though these things might be correlated.