It's called cognitive dissonance and relates to the fact that most people are not analytical and tend to make decisions based on emotional appeal (Since it's an election year, we're going to wallow in it until November.)
What these guys are saying is that I have an opportunity to be a gassaving SAINT

, because my cars suck lemons big time in terms of mileage, while the rest of you pikers are hardly making a dent in the problem with you puny 85mpg improved to 87mpg contributions.
Another alternate measure is gallons per week. Going 15 miles out of your way to stay on highways so you can avoid the three stop lights between where you started and the store 1/4 mile away makes for great mileage but is not really conserving gas. I generally filled the Brick (I guess it has a name now) around once a week (14ish gallons). In the month since I started this stuff (and not counting two exceptional cross countries) I'm running about 10 1/2ish gallons/week. So either I'm being more efficient and sensible about driving, or I'm building up a huge backlog of errands that are going to come due soon.