Talking about the visceral experience that games provide is difficult.
It is much like talking about why music has a certain "mood" to it or trying to decribe the feeling conveyed by an abstract painting. These experiences are so gut level that they are difficult to put into words.
I have been groping around for years for a way to convey to others the pleasure that I get from using the shotgun in a first person shooter. And it has finally come to me, it is the very definition of elegance: