Playing just a standard round of Call of Duty 4 when a clan hops on is fairly bad. I would consider myself to have above average skills in that game, but the rampant destruction and frequent death that happens when a well organized and skilled team takes the field makes me quit the game in short order. Actually, that happens a LOT in online FPS games and it's always annoying (The worst was tribes when your entire base would be destroyed, you'd have heavy armors camping all the spawn points and they didn't have the decency to even cap your flag enough times to win.)
Also, any stealth based game since thief. Doesn't matter which one - they all frustrate me because as far as I can tell I'm required to play through segments again and again in order to basically memorize patrol routes, timing, camera placement, infiltration/exfiltration routes etc. Hitman executed stealth well I suppose in the sense that stealth was more or less optional, and if all else failed you could always just shoot your way in.