1. Collison built Stripe's interview process around a test that shocked tech recruiters: candidates receive ancient, poorly documented codebases from failed startups and have 3 hours to fix critical bugs. No fresh algorithms or whiteboard problems — just archeological debugging. Most engineers hate it. The ones who thrive become Stripe's best performers. 2. The principle was real-world filtering. Collison realized that 90% of professional engineering is maintaining messy code written by people w