For some reason, I couldn't beat Cerberus the first time in Kingdom Hearts. I swear, I tried at least 20 times. And then my little brother was like, "hey, why don't you try using dodge roll?" I did, and I won. I won't ever do that battle again. It made me angry.

And then there was the time in FF7 when I used the save crystal in the northern crater near the top. And then I saved over my save file instead of a new one. I was so angry, I wouldn't touch the game for weeks. And then I got over it and beat it.