I love it when you spread out your party to avoid damage when an Ogre is about to hurl a rock or to avoid an incoming charge... and then your party still takes damage even if they're two miles away from the Ogre's line of sight.
Or when I nicely line up a Cone of cold when the game's paused, then I unpause the game, enemies move and I not only freeze the baddies, but also the rest of my party. R00fles!