EFFING SING, and such related moves (GrassWhistle, Hypnosis, etc), when they hit. AND THEY ALWAYS DO, because my luck is a big fat wad of suck.
I hate falling asleep. Two to seven (or so, I dunno) turns in which I can't do ANYTHING but sit there and take damage (And they can never have the decency to use it on my Tank, no.)
And if they use something like Mean Look before that... mmm, I SWEAR TO ARCEUS I'm going to kick 'em where it hurts... once I figure out where that is. Squish 'em like a bug.
And Protect/Detect, which always seems to come out when I break out one of my low-PP moves.
Rest and Synthesis and that kind of business, too... sends me into a swirling torrent of UNCONTROLLABLE RRRRRAAAAAGE.