Abstract Modern society operates on the assumption of “finished products,” “completion,” and “fully verified systems.”However, most systems that function in the real world do not exist in a state of true completion (1), but rather in a state of continuous convergence (0.99999…). This report begins with a simple question:Why do humans desire finished products,yet repeatedly experience accidents and failures in systems presented as finished? This report does not interpret accidents as technical flaws or management failures.Instead, it identifies the concept of “completion” itself as a cognitive default—a mental setting that causes human thinking to stop prematurely. The moment we trust something as 1,we misjudge a reality that always operates as 0.99999…. When this misjudgment accumulates, accidents become inevitable. This report defines the problem not as one of civilization, policy, or engineering, but as an issue of cognitive infrastructure, and proposes a new fundamental rule of thought for reducing systemic failure.