I don't even remember how many runs Qarn took me, but that was by FAR the worst one. I didn't have much issue with any other dungeon, or at least not enough to make a lasting impression. In order to not become very frustrated, I limited myself to only doing a few runs a day until I finally got the item. I've heard of people going 0/50+ on a certain dungeon drop, but that really is just extraordinarily bad luck.