You might be a hypermiler/ecomodder if:
While pondering buying a 49 cc scooter (80 to 100 mpg), you wonder if you can hook up a ScanGauge to it.
While pondering this same scooter, you wonder if you could realistically build a fairing so you can get "decent" mileage out of it.
You fantasize about putting lettering on said fairing when finished that reads "185 mpg - Priuses are gas hogs".
Your wife complains that you drive well below the speed limit on straight level roads, but then skid around the curves going downhill in the mountains while trying your best not to apply the brakes.