Now there's a title to grab your attention! But I'm serious!
First, a little background on me: my PhD was one of the earliest on the automatic creation of optimizing compilers from formal machine descriptions ("Machine-Independent Generation of Optimal Local Code", CMU Computer Science Department, 1975). After my PhD, I spent three years at CMU as a senior researcher on the C.mmp multiprocessor computer system which used our home-grown Hydra operating system, a secure, capability-based operating system. I then went back to compiler research on the PQCC (Production Quality Compiler-Compiler) project, which ultimately led to the formation of Tartan Laboratories (later, just Tartan, and now absorbed by Texas Instruments), a compiler company, where I was part of the tooling group. I spent a decade-and-a-half writing and using performance measurement tooling.
This essay has several parts and represents much of my own experience. The stories I tell are true. The names have not been changed, although a couple are carefully omitted.