If there's one thing that does get under my skin to some degree, it's when I have to repeat myself or redo something when I shouldn't have to.
I'm not talking about doing something again because you want to... But having to spend more time than you wanted doing something because you had to do it again. Perhaps because of an accident of your own doing, a freak accident that adds perplexion to frustration, or some ninny that messes up something who should have known better. Either way it boils down to having to do something again.
For instance, I had just started Tales of Legendia yesterday and was getting into it, looking forward to see what I would do next. Then I let a ten-year-old, who I had supposed had had enough experience with saving data (I mean, I've seen her save things before without a problem), play it when she asked. I should have trusted my gut and watched over her, but I'm too trusting... Or apathetic... Or something. Regardless, I now have to redo twelve hours worth of work. Might've been alright if I had already finished the game and wanted to play through it again, but I want to make progress and see what happens next, not go through what I've already done again. Especially since I had just started it! >.<
Fortunately, I cool off pretty fast, so I usually just steam to myself for a few seconds before I return to my usual placid, dead-to-the-world self. <.<;