I walked out of the room to get a snack and f@$&ing Windows restarted to install updates. I was eight or nine unsaved pages in to a paper. I lost it all. That was more than a decade ago, so even on Google docs, I will ctrl-a ctrl-c my entire document every time I pause for a second, basically every few words, until I see it saved successfully.
The newer versions of Excel and Word do this for you now. If you ever find yourself in that situation, open up the program again go to file -> open -> recent -> then scroll all the way to the bottom and click "recover unsaved workbooks". It's come in handy several times!
*puts in a full stop* *ctrl s*