Occurs after playing many hours of any gta game. The victim forgets that they are not playing gta and constantly thinks as if they are in the game. This includes thinking about which car you should take and what would be a sweet jump to go off of, getting frustrated because there aren't any missions on your gps, and trying to figure out why you cant get a damn prostitute anywhere.
Guy 1: Dude!!!!! Why the fu*k are you driving on the Sidewalk!?!
Guy 2: Oh my bad. I have GTA syndrome.