How do you lose 900 million dollars in 100ms? Or 8 million visits in just 4/10 of a second? User expectations are higher than ever when it comes to web performance, so much so that we've created an entirely new application architecture just to make it feel like our websites are faster than they actually are. This talk will look at how we can improve our users experience at any scale through performance optimizations at every layer of the stack, from backend to browser.