Monitoring the right metrics in AppDynamics helps ensure smooth and optimized web application performance. The most essential ones include response time, throughput, and error rates, which collectively indicate system health and user experience quality. Additionally, database call duration, memory utilization, and CPU load are vital for diagnosing backend bottlenecks. Frontend metrics such as page load time and user interactions can highlight UX issues. AppDynamics also allows for correlation of these metrics with business KPIs, helping teams understand the direct impact of performance changes on revenue or customer retention. Focusing on these key data points ensures proactive optimization rather than reactive firefighting.