Your Monitoring Didn't Miss the Incident. It Was...

I've watched observability vs monitoring play out as a live incident more times than I can count. The dashboard was green. The on-call engineer was not paged. The monitoring system did exactly what it was designed to do — it watched for thresholds, waited for metrics to cross them, and stayed silent when they didn't. The problem is that modern systems don't fail by crossing thresholds anymore. They fail by behaving differently. Latency doesn't spike — it drifts. Error rates don't explode — they