Go

An evening with GODEBUG=schedtrace=1000 taught me more about what my service was actually doing than a month of metrics

A team I consulted with had stuffed request-scoped configuration into context values and it was slowly eating their tail latencies

sync.Map looks like a drop-in replacement for a map with a mutex, but for most workloads it's slower and harder to reason about

A slow creep in our billing service's memory graph turned out to be goroutines blocked on a channel nobody was draining