Either this was poorly written or the author just doesn't get it. Developers shouldn't do TDD or 100% code coverage because they want to build a perfect system; developers should do TDD because they understand that they can never build a perfect system and the T in TDD protects them from complete failure. This means you never attempt to build a perfect system; you only attempt to do just enough. What is just enough? It is the amount of functionality to make the tests in TDD pass... never the amount of functionality to make others 'fall down on their knees and claim “we’re not worthy!”' Thought I'd also add that technical debt is unavoidable, but we realize it is not OK to have technical debt (the article concludes that technical debt is OK) and that is why we back it up with tests. These tests are like collateral for a loan (technical debt).