The author of this text is an engineer who emphasizes the importance of treating application performance like a feature. He shares his experience with using Sentry, a tool for monitoring and analyzing performance issues, to transform vague problems into concrete, actionable ones. The author argues that users care deeply about performance and notice even small improvements. To prioritize performance effectively, he recommends transforming abstract woes into concrete issues, defining and contextualizing user pain, and elevating ad-hoc decision-making to contractual obligation through processes and tests.