Way too many things. I'll go with just two games here though. Assassins Creed: I'm going after the templar garrsion commander. I've climmbed to the top of the walls, killed the archers quietly, climbed down to the lowest point that I can inside. I attempt an aerial assassination. Altair misses and lands face first on the cobbles between the commander and the soldiers he's been shouting at.
Red Dead Redemption. Specifically, online griefers. More specifically, two bastards I met when I was only level 4 or something. It started innocently enough. I encountered them on the map. One guy I ignored, one guy I shot in the head. Once, just for the fun of it. (Two seperate occasions, by the way.) This guy then shot me back, killing me several times. The guy who I never shot did the same. After many deaths, I decided to just run. Both of them kept killing me, with weapons like sniper rifles and dynamite, which I couldn't match at my low level. After something like 30 deaths each, I was just riding flat out trying to escape, and still the rape continued. One guy had a much faster horse than me, so I just had to quit. The guy who I hadn't shot the first time chased me from Mexico all the way to Blackwater before continuing to kill me. I eventually quit there as well. People who do this are annoying, but at least if you're on the same level as them you can kill them back some times, and it makes them a lot more likely to get tired of it. These high level bastards though...