I got a good long way into Turok II on the Nintendo64, when the little kid my sister-in-law was babysitting came rushing by me going hellbent-for-leather.
I thought she was going to knock my machine off the stand so I swooped down to cover and protect it, but I stumbled in my haste and disconnected the whole thing without saving a bit of it.
I couldn't bring myself to play it after that, I was so mad and dissapointed at myself. (and the kid, truth be told)

I still get a pang in my heart thinking about it to this day.
