I spend a lot of time rubbing elbows with John and Jane Wolfpack, and there are numerous times where a heavier, fat tired, full suspension bicycle just won't be advantageous, and the extra effort and time spent will eventually grow old, especially if one spends a lot of time in the saddle. Usually when I want to spend a little more time and effort, is when I go to the grocery store and return home with 50 lbs or more of items.
The only time I knew that I had the "wrong" bike, is when I got dropped by an elderly woman riding an old English three speed with a horribly squeaky chain.