A friend of mine got me on Gentoo in 2004. He spent all of his time tweaking compiler flags like -O3 -ffast-math -fomit-frame-pointer -funroll-loops and running into so many issues in the process. I think he only lasted about 9 months on Gentoo. To this day, he's the only person I've ever met that was there for performance.
I'm still on Gentoo 22 years later.