The Pragmatic Designer: Ur-Technical Debt.

Ur-technical debt is generally not detectable by static analysis. Despite that, there are plenty of tools that promise the world, and will examine your codebase and deliver a list of issues labeled “technical debt” for you to fix. Their output is a small fraction of the real debt because ur-technical debt happens when my ideas diverge from my code, and my thoughts are stubbornly hidden from static analysis tools.