Holy cow.  Did someone delete your game or something? O.o

Yeah accually. I was at a friends house, this was a while back. I left my gameboy inside, and I believe we wen't outside or something. Came back in, turns out his little brother deleted my file, and started a new one.

Although I didn't lose it to the game's design, but I still lost it!

Yeah that really hurts.  Same thing happened to the Super Mario Galaxy file a friend of mine had not too long ago.  He was almost done then *bam* a friend of his deletes it.  That stuff really sucks.  He never replayed it but I showed him the end on mine.

3 years of playing and saving 20+ wii games.....(wii died a few weeks back)

other than that proably about half the N64 games a lent to my one neaibour always came back with all the save files deleted...I lost my penquin board and ice man in 1080! :(

not form game design but when my friend moved to Texas he took my ps2 memory card with him

Dirge of Cerberus: Final Fantasy VII 50 hours
Final Fantasy X 130+ hours
Final Fantasy X-2 70 hours
Final Fantasy XII 120 hours
God of War 20 hours
God of War 2 30 hours
Kingdom Hearts 100 hours
Kingdom Hearts 2 120 hours

In FF4 and FF6 actually.... and FF1 i think... i've gotten to the final area... to the final bosses. With what turned out to be horribly underleveled parties as one hit would be enough to kill my beefiest guys.

In LittleBigPlanet I had aced through all the main story modes trying to get a trophy but the game wouldn't save my data. It was only afterwords that I realized that I had too many community items making my game unable to save. So I lost about 10 levels of perfect playthroughs and had to replay each one to finally get the trophy.

well i played for like five hours and then got off( thinking the game had a auto-save feature)