I filled the tank today, did the gas mileage calculation and came up with:
There was an old Walter Matthau movie where he had a neighbor who wouldn't stop bragging about the mileage his VW was getting. So Matthau and his little boy started sneaking over and adding gas to his tank. The neighbor bragged even more, of course, until Matthau & Son started siphoning gas. Maybe my friends saw the movie and are playing the same trick on me.