Average Response Time Looks Fine but the App Is Slow: Check p95/p99
Your average is diluting the slowest requests. Latency distributions are right-skewed, so a few multi-second requests barely move the mean, and those few are what customers remember. Track p50, p95 and p99 from histograms, broken down by route. Then trace the slow requests to their cause, which is usually GC pauses, cold starts, N+1 queries or a saturated dependency. Do all of that before anyone quotes you a rebuild.