The excessive urge to complete as much of a game as possible, in order to obtain achievements, trophies etc.
More often than not, the task involves completing a specific stage on a difficulty level that one normally struggles with, and due to the achievement, they push themselves to get it, often repeatedly failing at one point, and eventually getting beyond frustrated over it, becoming difficult to interact with during this moment of anger.
Jack: "Hey, what's up with John? I was going to ask him if he's going out today but he was obviously pissed off in the way he responded."
Joseph: "He's experiencing gamer's curse."
Jack: "Oh, please...how people get so worked up over games is beyond me."
Joseph: "Hey, if you'd spent over an hour trying to clear something that can be done in under 10 minutes, and you STILL hadn't done it, I'm pretty sure you'd be pissed off, too."