Congrats, you deployed your Node app to prod! But how do you actually know if your users are having a good experience? Logs are great initially—until your dashboard becomes overwhelming. We could add metrics but they have a steep learning curve. In this talk we'll see where console.log falls short and learn how metrics help us better define what a good user experience is. We'll also discuss why useful code instrumentation is hard, and propose what we can do to make it easier.