My worst moment was when I was playing Diamond with my friend, so he was playing through at this time. We had beaten the last gym and all the Team Galactic stuff and my friend had just passed Victory Road. So as he was handing the game to me so I could battle the Elite 4, his finger hits the power button (this was on the original DS) and 5-6 hrs of our time just disappeared. I was so sad after that... It was horrible.
Regarding PKRS, I got lucky and obtained it in Platinum on my rerun through it. I couldn't believe it when I saw it, moreso because I only caught ~9 wild pokes throughout the main storyline.
VM for an OU/LC rate.