I remember one time when I was writing in google docs. Google docs saves as you go, so every 3 seconds or so it automatically saves for you. There's no need to go to file--->save or any commands like that. It saves as you're typing. Which is great.
Or so I thought.
I had the whole 60k highlighted for some reason and accidentally hit delete. Of course, within three seconds it saved my "work" aka: my blank document. Then I panicked and went to hit undo but for some crazy reason (I was panicking!) I closed the file. I think I aged six years in the time it took me to reopen the blank file and stare at the empty screen.
I lost a bunch of work, but I had backed it up only a week ago, so not too much was lost.
But damn it, I've never gone without backing up my stories in multiple places after that. Google docs, MS word, email stories to myself, I have an external harddrive, and thumbdrives. Sometimes I even print them out and put them in a file cabinet in case there's a massive black out or something.
Losing work is such a bad feeling.
It instantly kills any and all creativity for about a week (for me at least)