This was back in the 70’s. You would pick up the nozzle and lift the thing where the nozzle was previously sitting, then squeeze the trigger to pump gas. When finished, you would push the thing back down and replace the handle. Pulling the trigger with the thingie in the down position allowed gas to flow out of the hose without pumping additional gas.
Does that make sense?
In some areas (especially with older or independently-owned stations) they still have these pumps.
This is the case at many stations here in New Mexico, particularly in rural areas, such as, well, here. We have a big lever upon which the handle rests which, when lifted, sets off a little beeping noise and probably a flashing light inside. The attendant then presses a button or flips a switch or something, and the pump starts up. The trigger then, presumably, merely opens a valve in the nozzle.
Pushing down the lever deactivates the pump, after which you can still press the trigger to open the valve.
The attendant also can set the pump to switch off after you’ve reached a pre-paid amount. Pre-payment is often required after dark, although most places don’t worry about it if they know you.
When out of town, I often try to lift immobile nozzle rests, and I suppose there’s a few kids who wonder what the heck I’m doing. I suspect that people who shake the hose when it’s futile grew up with the older design and got into the habit.
Huh. I do this, but I do it because I don’t want the gas to drip onto my car or the pavement where it then evaporates into the air and contributes toward pollution. Gas fumes are a major contributor to smog. I never thought about whether or not its “paid for,” I guess I always assumed it was.
I feel like such a tree-huggin’ hippy now…
But I wonder how much you use that gas hog to carry 14 people. 
ps I have a gas hog also… a F-150 Super-cab, that I seldom use to carry anything but my wife and I. :smack:
Sort of a hijack, but…
Our pumps have a label promenently posted, advising customers that, because of the way the vapor-recovery systems work, you shouldn’t top off the tank once the valve has clicked off. Doing so apparently lets vapor escape.
Every time I see that label, I wonder: What beaurocrat in what annonymous office every thought that putting that label on the pump would ever deter even ONE customer from topping off his tank? What fantasyland does HE live in?
Yet you drive a car?