Hmm, let's think.
On Abe's Exoddus, I got right to the last bit of the part where Abe returns to the Mines, but fell down a pit. I meant to hit restart path, but accidentally hit Quicksave. This caused it to forever remain on a blank screen- Abe hjaving fallen down the hole. He didn't respawn, no matter what I did. It was damn annoying.
Also currently on Fifa 07, I was trying to make an all custom-player team, but accidentally hit 'random face' when creating the next to last player's appearance. Now whenever I try to make a new player, they turn into a shrivelled-faced person who looks like a black-skinned prune, and in player mode, their face is all distorted and they're bald. I can't fix it, whatever I do. Really annoying.
However I encountered something very satisfying recently. Just before Christmas, having pretty much exhausted all my games, and not yet having an ynew ones, I went back and played Spyro 3 again (This'll cheer you up Daxter
). I had never got past the third boss, who's like a giant dragon who throws eggs at you which have crabs inside. You need to collect rockets and shoot him with them. I beat it first try and got to the last world, which I had never been able to do. So yay me.