Generally, it's always bad to generalize...generally speaking that is.
My personal experience on this subject:
My wife thinks I'm goofy for the things I do to my car, but doesn't care as long as I don't spend hardly anything doing it. She tried once to figure out the FE of her car but gave up after one tank. Her 2000 Mazda Protege LX gets about 26 MPG the way she drives it and she's ok with that. She gets a little annoyed when I remind her that my car gets double the mileage hers does.
My first girlfriend was so taken with my addiction to FE that she made her parents get an HCHII when she started driving, even though her family almost exclusively drives <20mpg vehicles (2006 viper, H2, bmw 750lxi [or whatever the most expensive kind is]).