Gonna tell you a story that my uncle likes to tell.....(every time I see him. Please understand that old folks tell stories over and over not because they forget that they have told it to you, but because they want you to actually remember them.)
Back in the 1960's he used to work at McDonell-Douglas in Texas. There was a guy they used to work with who had just bought a Volkswagon Beetle. He was constantly raving over how good the gas mileage was. Everybody else was driving gas guzzling Detroit models back then, Buicks, Chryslers, Fords and other popular 'Land Yachts" of the day.....of course gasoline was probably 30 cents a gallon.
"Why, it gets xx_mpg!".....He went on and on about it, and someone thought of a funny prank to pull on him. Somebody would go out in the parking lot and put a gallon or two of gas in the 'Bug' every day or so.....He would come back and say "Wow, you guys, you wouldn't believe it, I've driven for days and the needle hasn't even moved on the gauge! This thing is really great!" Of course everybody know what was going on so it made his bragging hilarious. When they stopped doing it, it was like, "Well fellas, I don't know what happened, I was getting really,
really good gas mileage, then something happened" and thought he might have to take it back to the dealer or something....or so the story goes.