My desire to drive fast (my sweet spot is 78mph on the highway) is based solely on how far I have to drive when I do drive. I travel off of the farm less than once a week. But when I do leave the farm I can easily put 150 miles on the truck getting everything done that needs doing. And the bulk of that is on the freeway, once I get to it.
Or travelling to see my sick mother once a month (1200+ mile round trip) or my daughter as often as possible (1600+ mile round trip). Add to that I am on the large side of the equation at over 6'3" tall and near 300 pounds, and getting my v8 powered truck (20+ mpg) away from me will be a challenge.