Explore the Observer/Observable APIs and their potential to simplify common development challenges in this conference talk from JSConf Budapest 2017. Learn about Intersection Observer for efficient lazy loading and scroll handling, Mutation Observer for tracking DOM changes, and Performance Observer for gathering real user metrics. Discover how these modern APIs can replace traditional solutions, making code more efficient and easier to maintain. Gain insights into compatibility issues, polyfills, and the future of browser observations with ResizeObserver and ResizeObservables.