Of course the problem with the "I don't get window sticker fuel economy" argument is that there is never any claim that a person would get that fuel economy.

The window sticker fuel economy is merely what the manufacturer got when running the tests as instructed by the federal government. To see how these tests are run, look here:

http://fueleconomy.gov/feg/how_tested.shtml

(you can also click the 'detailed' test info link on that page to see the new tests).

The window sticker is merely a shopping guideline so that a consumer can determine which cars are likely to get better fuel economy than others.

There are only two ways to get the federally scored window sticker fuel economy when driving your car.

#1 Drive your car on a dynanometer instead of on the road, and make sure you drive it EXACTLY as the profile instructs in the federal testing guidelines. Even then the score is merely an "average" of several sampled vehicles.

#2 Get very very lucky that your average real-world commute happens to be identical to the testing profile of #1.

If you don't happen to fit the exact profile of 'average' then "your mileage may vary".