Battle Tower, Battle 163. First Pokemon out is the 645 Skarmory, which gets locked into Night Slash by my Latias. Switch to Scizor, set up Sub, +6 with Swords Dance, Brick Break twice and I win.
Next Pokemon out, 934 Heatran. My team (Latias, Drapion, Scizor) hates Heatran in general, but so long as I have a Sub up, Scizor will never lose against any of them (theoretically).
I use Brick Break, Brightpowder hax makes it miss. Flamethrower breaks Sub. I use Brick Break again. IT MISSES.
Me: OMGWTFGODDAMMIT!
Heatran: *Flamethrower kills Scizor*
So now I'm in deep trouble. I send out Latias, intending to T-Wave and Flash the thing to death. T-Wave hits, Heatran uses Dragon Pulse, CRITICAL HIT!
Me: *shuts game off*
I just gave up. Drapion had absolute zero chance against a Modest Heatran, its only attack is Crunch. Nothing I could have done, just got totally owned. The chances of that happening? BP1(1/10) X BP2(1/10) X CH(1/16) = My loss(1/1600).
That just ruined my day entirely. The worst thing happened the next day, when I was watching the Battle Video (no, I don't have Wi-Fi, so don't ask). I realized how infinitely idiotic I had been, not using Drapion to set up Accupressure against Skarmory. I would have won with ease if I had done that. Needless to say, that whole week sucked to high heaven.