I also tend to have important stuff in a buffer before doing anything destructive outside emacs although I definitely keep backup files on.

Reminds me of a time a hard drive failed on a computer I had. I had an active ssh connection, running terminal display emacs remotely, with a very important file -- with no backup copy -- in a buffer. The computer continued to function, but I couldn't access the disk at all, and I figured as soon as I closed the ssh connection, it was game over. I managed to salvage the file by cutting and pasting through my terminal emulator.