I had a similar experience where I tried to declare bankruptcy after havning not used emacs for a year and a half or so, ended up re-implementing things until finally I was like 'no I was right the first time'.

That said, damn, my emacs config is like 1000 LOC and takes like 20 seconds to load. Also the reason I keep leaving Emacs is definitely the complexity of the bugs and the edge-of-the-edge case things that come up when I'm just trying to do something simple (the other day it crashed after running `e: newfile`, the evil mode command for editing a new file. I have no idea why it crashed but after it did the program couldn't be killed. Maybe it was because I was trying to open a file with no extension, but even that's a stretch.

Anyway would you mind if I sent you my config sometime or looked at yours? It's never occurred to me to write regression tests