Originally Posted by ElanC

It's not using a lot of fuel. It's just getting poor gas mileage for the very short distance driven. Let's say you're completely stopped with the engine idling, and you do so long enough to use one ounce of gasoline. Since you're stopped, your instantaneous mileage (IM) gauge will show zero and you won't worry about it.

Now let's say that during that time that you used an ounce of gasoline you crept one foot forward. Your gas mielage over that one foot will look awful. (If you want to do the math, an ounce per foot is about 5000 ounces per mile, which is about 40 gallons per mile, which is 0.025 MPG. That's downright AWFUL). But why worry about it? You've still only burned one frikin ounce of gasoline.

By the way, this is just an example. You actually burn a lot less than an ounce of gas when you stop your car for a few seconds or creep forward a couple of feet.