Mungriness usually surfaces from impatience during unfortunate near-meal situations such as slow service in a restaurant, having to wait on someone before eating (for any reason), and generally being so hungry that all of the world seems like a terrible place (usually followed by an intense, temporary obsession with a particular kind of food--most commonly, wings).
Dale: Yeah, man, we better eat something soon. I'm starting to get mungry.
Note: It is impossible to eat a mungry.
Andrew: Wow look over there