When playing my first playthrough of FFVIII my brother started playing the game cause it looked "interesting" and ended up saving over my game file... I was half way through disk 3 and had taken time to level all my current characters to a decent level (fighting Malboros) and had gotten the Lionheart and my GF's were mostly maxed out (thanks to the cactuars).since then I decided that I would save to 2 different slots just in case he did it again.

I also stopped playing Grandia II for some unknown reason, picked it up at random to show a friend what it was like and completely forgot the reason I had stopped playing in the first place, since then I have always been determined to play a game the whole way through no matter how sucky it was (like Arc: Twilight of Spirit).