@fl42v I have thousands from my early days, but my only recent-ish one was pretty funny.
On an Arch install that hadn't been updated for a while, in a rush, had an app that needed OpenSSL 3. Instead of updating the whole system, I just updated the openssl package.
Everything broke immediately. Turns out a lot of stuff depends on openssl. Who knew?
To fix, booted to the arch installer, chrooted into my env, and reverted to the previous version of the package — then updated properly.