People like to get all they can out of things. It could be eating the crumbs at the bottom of a bag of chips or shaking the gas pump nozzle to get those last few drops. Hey, you paid for that gas.
RATESDOTCA gives us this ad illustrating what it’s like to overpay for car insurance. Some insurance companies might milk you as much as they can, and it’s udderly cruel. Although it’s not usually so literal as it is in this case.