If only the dash readout were accurate…
Otherwise known as the 'wish-0-meter', they tend to run about 10% optimistic.
I haven't told my wife, that way I can point to it and say see, I'm getting about 17.9 MPG (in reality it's closer to 16MPG).
I was bummed the first time I took a road trip and it was reading 16.5 (admittedly, going 85mph across KS) I knew I was only getting around 15.

Now when I cross KS, if I'm not in a hurry, we'll take HWY 24 just to the north of I70. It's prettier. Adds about an hour/hour and a half but we save a little money and have a more enjoyable trip. Sometimes it's nice to slow done and see the countryside.
My old Jeep Wrangler I6 was getting about 14mpg, so at least the V8 in the 4R was a slight improvement in efficiency. A huge improvement in creature comforts!