i've never ragequit because of people, but the Shitty servers for CoD:MW2 pissed me off to no end, i can't count how many times the servers would lag on me, often i'd get stuck in doors, and get killed because i was trapped in an infinite loop, running backwards and forewards through the door, or empty an entire clip into an enemy's face, only to get killed by him because the lag was so bad i was shooting at where he HAD been and he was already behind me.
so i just yelled out What the FUCK and left, never touched another Call of Duty game after that.
i've been tempted to quit in GTA before because some assholes take every little thing personally, or camp near the helicopters and blow them up, like this one person (i actually think i made him ragequit instead), who followed anyone in a helicopter around and shot at them, (i just wanted to dick around) and the moment i showed him who was the boss (IE: Blew his ass out of the sky) he decided to spend the rest of the game hunting me down, no matter where i was, i could understand the first time, but he must have been some pissed, because he spawn camped my ass, probably killed me about twenty times, ran me over with cars, shot me, and even resorted to hunting me down with a helicopter, and i've been trying to defend myself from him too, the last time he was so obsessed with getting me i was actually able to lure him into a trap, he crashes his hellicopter, i take off into cover, i shot him down, he quits the game, it's funny to see how people take being put in their place, ragequitters are a prime example of that, because they obviously cant cope with losing a match in an online game, imagine how they'll react to losing a girlfriend, not getting a job and so on, besides, every time i lose it forces me to reevaluate my strategies, which is healthy