Within the observability community, there’s a saying, “nines don’t matter if users aren’t happy,” meaning that 99.999% server uptime is a pointless goal if our customers aren’t having a fast, smooth, productive experience. But how do we know if users are happy? As members of the web performance community, we’ve been thinking about the best ways to answer that question for years. Now the observability community is asking the same questions, but coming at them from the opposite side of the stack. …