When my daughter was very young, she deleted my Mario Kart DS save. I was bummed, i had worked hard on it. But it gave me a really good excuse to play again!
When I was a kid, I accidentally deleted my ol' man's save file on Link to the Past, while opening a file for a friend. I swear, it is the only time in my life, where I looked at my dad and genuinely thought he was going to beat the shit outta me... A few years later, my girlfriend, at the time, deleted my Manhunt save file - I'd been playing on Hardcore. Looking back, and knowing how he must have felt... The ol' man would have been justified!