Entrepreneurs On IG on Instagram: "In 2012, Brian Armstrong pitched Coinbase during a Y Combinator practice session that later became part of startup folklore. While explaining his idea, Paul Graham interrupted him with simple pointers. At the time, Coinbase was trying to solve a basic problem. Bitcoin wallets were confusing, slow, and built for technical users. That short rehearsal helped sharpen the final Demo Day pitch. By focusing on growth instead of theory, Armstrong aligned with what Y Co