In this talk we will look at how to collect, analyze, and act on a few metrics that tell us more about how our user feels when using the site. We can trend how these metrics change over a user’s browsing experience, and we can improve over time the metric that really matters: user happiness. Some of the metrics we’ll look at are: Rage clicks, missed clicks, and dead clicks; Cursor thrashing; and LD50 (median lethal dose). We’ll try and correlate these metrics with things that are easy to improve developmentally, like smoothness, jank, visible transitions, and more. At the end of this talk you will understand which metrics are useful to measure, how to measure them, and how to tie them in to your development goals.