For me it was “The Most Controversial Children’s Book in History” by Solar Sands, in which he analyzes The Giving Tree. It led me to think about my relationship with my parents, and about what kind of relationship I might have with my kids if I ever become a parent.
I can’t say recently, or maybe I can’t think of one. But if I look back two come mind:
BobbyBroccoli and his assay on Jan Hendrik Schön were several hours of: wtf?! Watch it on Nebula if you can.
Several talks from David Kriesel at the CCC. I loved them all but the Xerox talk really surprised me.