The Most Dangerous Response Code Isn't 500. It's 200.

A deployment can return HTTP 200 OK yet still serve broken pages, because 200 only means the request succeeded, not that the content is correct. The article lists six “silent failure” patterns: phantom deploys, MIME rejections, redirect loops, ghost servers, API‑gateway masking, and third‑party outages, and recommends real‑user monitoring to catch them.