I put my home directory on another partition, because I heard very early on that it can better facilitate distro hopping. That is not the stupid part, that’s actually good advice.
The stupid part was assuming that Linux users are identified by name, and that as long as I create a user with the same name as the one on my previous install, things would Just Work.
Im reality, Linux users are integer IDs under the hood. And in my original system, my current user at the time was not the first user I had created on that system. Thus, when I set up my new OS, mounted the home partition, and set the first user to have the same name, I was immediately unable to log in. The name match meant I was trying to read my home dir, but the UID mismatch was telling me I had no permission to read it. I was feeling ballsy with the install and elected to not enable the root user, so I had an effectively bricked OS right out of the box.
I’m sure there was some voodoo I could have done to recover it on that attempt, but I just said screw it and reinstalled.