From the New York Times:
[R]esearchers have found that people are often lured into making decisions by numbers that seem bigger than they really are....
The researchers asked volunteers to take part in a behavioral test known as the prisoner’s dilemma, in which two partners are offered various rewards to either work together or defect....
Happily, we can exploit our sad innumeracy to enhance self-esteem. For instance, if you're gaining weight, use kilograms, but if you're losing, use pounds ounces. (I've lost 14 in the past two weeks alone!)
Political applications? Use pounds (here as opposed to dollars) to report the amount of taxes Timothy Geitner, Tom Daschle and Nancy Killefer haven't paid.
UPDATE: Another possible political application here in which measuring systems from Old Europe might have been preferable. Or I guess you could just use inches. (It would makes the absolute difference so much bigger.)