"Feature complete" answers only one question: do the features work in the lab? It says nothing about whether the system survives **production** — armies of illogical users, globe-spanning traffic, virus-writing mobs, and three-to-ten years of continuous uptime. Nygard's opening puncture: passing QA tells you little about suitability for the system's actual life span. Even agile, automated, pragmatic testing cannot reproduce the stresses of the real world. Testing proves the system *does what it should*; it cannot prove the system *won't* crash, hang, lose data, or lose money under real-world load. The trap is aiming at the wrong target — building to survive the artificial realm of QA ("the middle initial is optional") instead of the real world of production. A system can pass every test and still be the Chevy Vega of software, falling apart the moment it leaves the lab. --- *Source: [[Release It Second Edition]] (Michael T. Nygard, Pragmatic Bookshelf 2018) — Ch 1 — Living in Production*