Have I been doing it wrong all these years?

fj12ryder wrote:
The main thing to remember is that the MPG reading is a lie. If you really want to know your MPG, keep track of mileage and amounts added to the tank, over several tankfuls you'll get your pretty accurate MPG.

Let me understand. You trust your computer to tell you the number of miles you traveled. You trust your computer to tell you how fast you are going. You trust your computer to tell you the amount of time you traveled. You trust your computer to tell the engine what your foot wants it to do. You trust your computer to mix the correct amount of fuel with air, to allow the engine to run correctly.
But you don't trust your computer to be able to use all that information to figure your MPG? Instead you trust a hand held computer, and a simi accurate computer on a random gas pump on a simi level concrete pad to figure your MPG. Oke Doke!