Usually the player is trying to show that they clearly know more about a video game and are mocking other peoples knowledge of said game.
Unfortunately it's just a fucking game and knowing more about interactive fiction than having social/survival skills classifies the player as a total douchebag and most likely to be the first to die when presented with a life or death situation.
douchebag player: "*sigh* Stop playing the game, your stupid question annoys me."
noob player: "what a douche"
Real World Scenerio
Frantic Person running by: "Oh my god! Some guy has snapped and is on a killing spree! Get the fuck out of here!"
douchebag player, thinking to him/herself: "*sigh*, if only I could use invisibility, just like in my favorite game, I could....Ahhh!"
The douchebag player has been killed by the rampaging psychopath.