A system being “up” does not mean it is healthy. Customers can experience slow responses, failed transactions, or inconsistent behavior while every server still appears online.

That is why observability matters. I want a production system to answer simple questions quickly: What failed? When did it start? Who was affected? Where did the delay happen? What changed before the problem appeared? Logs, metrics, and traces are not just debugging tools. They reduce the time between discovering a problem and understanding it. Good engineering is not only about building systems that work. It is also about making failures easy to detect, explain, and resolve.