Tinkering is all fun and games, until it's 4 am, your vision is blurry, and thinking straight becomes a non-option, or perhaps you just get overly confident, type something and press enter before considering the consequences of the command you're about to execute... And then all you have is a kernel panic and one thought bouncing in your head: "damn, what did I expect to happen?".
Off the top of my head I remember 2 of those. Both happened a while ago, so I don't remember all the details, unfortunately.
For the warmup, removing PAM. I was trying to convert my artix install to a regular arch without reinstalling everything. Should be kinda simple: change repos, install systemd, uninstall dinit and it's units, profit. Yet after doing just that I was left with some PAM errors... So, I Rdd-ed libpam instead of just using --overwrite. Needless to say, I had to search for live usb yet again.
And the one at least I find quite funny. After about a year of using arch I was considering myself a confident enough user, and it so happened that I wanted to install smth that was packaged for debian. A reasonable person would, perhaps, write a pkgbuild that would unpack the .deb and install it's contents properly along with all the necessary dependencies. But not me, I installed dpkg. The package refused to either work or install complaining that the version of glibc was incorrect... So, I installed glibc from Debian's repos. After a few seconds my poor PC probably spent staring in disbelief at the sheer stupidity of the meatbag behind the keyboard, I was met with a reboot, a kernel panic, and a need to find another PC to flash an archiso to a flash drive ('cause ofc I didn't have one at the time).
Anyways, what are your stories?
Can't say I have any interesting stories. Most of mine are just the head-scratching "I don't know why that didn't work; guess I need to reinstall" kind of story. Like enabling encrypted LVM on install and suddenly nothing is visible to UEFI. Or trying to switch desktop environments using tasksel and now I have a blank screen on next reboot. That lame kind of stuff.
My coworker though... he was mindlessly copy/pasting commands and did the classic rm -rf $UNSETVARIABLE while in / and nuked months of migrated data on his newly built system. He hadn't even set up backups yet. Management was upset but lenient.