<3 I always love seeing your comments and questions, too!
Well on the subject of PHP, I think I've got a nice story.
The more recent one is about Wordpress. One day, I had this conversation:
Boss: "will the blog stay up?"
toast0: "yeah, nobody goes to the blog, it's no big deal"
Boss: "they will"
toast0: "oh, ummmm we can serve a static index.html and that should work"
Later that day, he posted https://blog.whatsapp.com/facebook I took a snapshot to serve as index.html and the blog stayed up. A few months later, I had a good reason to tear out WordPress (which I had been wanting to do for a long time), so I spent a week and made FakePress which only did exactly what we needed and could serve our very exciting blog posts in something like 10-20 ms per page view instead of whatever WordPress took (which was especially not very fast if you hit a www server that wasn't in the same colo as our database servers). That worked pretty well, until the blog was rewritten to run on the FB stack --- page weight doubled, but since it was served by the FB CDN, load time stayed about the same. The process to create and translate blog entries was completely different, and the RSS was non-compliant: I didn't want to include a time with the date, and there is/was no available timeless date field in any of the RSS specs, so I just left the time out ... but it was sooo much nicer to run.
Sadly, I haven't been doing any large scale optimization stuff lately. My work stuff doesn't scale much at the moment, and personal small scale fun things include polishing up my crazierl [1] demo (will update the published demo in the next few days or email me for the release candidate url), added IPv6 to my Path MTU Discovery Test [2] since I have somewhere to run IPv6 at MTU 1500, and I wrote memdisk_uefi [3], which is like Syslinux's MEMDISK but in UEFI. My goal with memdisk_uefi is to get FreeBSD's installer images to be usable with PXE in UEFI ... as of FreeBSD 15.0, in BIOS mode you can use PXE and MEMDISK to boot an installer image; but UEFI is elusive --- I got some feedback from FreeBSD suggesting a different approach than what I have, but I haven't had time to work on that; hopefully soonish. Oh and my Vanagon doesn't want to run anymore ... but it's cold out and I don't seem to want to follow the steps in the fuel system diagnosis, so that's not progressing much... I did get a back seat in good shape though so now it can carry 5 people nowhere instead of only two (caveat: I don't have seat belts for the rear passengers, which would be unsafe if the van was running)
[1] https://crazierl.org/
[2] http://pmtud.enslaves.us/
[3] https://github.com/russor/memdisk_uefi