Fantasy and Reality
Fantasy is only effective within a certain range of "truth". That's the reason why we can say in the middle of a video game "well that doesn't make any sense". If you think about it: nothing much in an RPG, on the whole, makes sense. But it's that shred of realism and its play with fantasy that makes for the most effective RPGs.
The play between fantasy and reality is often effectively portrayed when it comes to plot and characterization. Love stories, evil overlords, and funny distractions all follow a genre that has been set forth pretty straight-forwardly for hundreds of years. But when it comes to gameplay mechanisms, the abstraction of video games often causes a huge (too huge) loss in realism.