Slow API endpoints compound downstream.
Every slow API endpoint slows down every frontend that calls it — the web app, the mobile app, the partner integration, the admin panel. A typical untuned Laravel endpoint fires 30 to 60 queries via N+1 problems and missing eager-loading; a properly tuned one fires 2 to 5. The user-facing impact is real: a SaaS dashboard that takes 3 seconds to load on every page transition is a SaaS product nobody wants to use. Most teams have no idea because they only watch the average and the average hides the slow tail.