#debugging

Your checkout logs a line at every step, which looks like good observability. Then a customer says their payment failed, and you find out what those logs can't tell you.

You're about to add logging to a new service, or you're staring at an existing one where every incident turns into a grep-and-guess session across a dozen disconnected log lines. Replace the step-by-step logs with one wide event per request.

Something's on fire in production and you're the one holding it. Your job for the next fifteen minutes is to shrink the impact and coordinate the response, not to find the root cause.