Here's a great example of a valid reason for using a headset. But, I'm guessing that SANguru doesn't walk around the grocery store at 9 am on a Sunday morning with it stuck in his ear with nobody to talk to, though. While wearing a coat over his pajamas (yes, I have, much to my dismay, been witness to such a sight. More than once)

One of my best friends is a truck driver, and I told him last year to go buy a bluetooth headset. Truck drivers are unable to function unless their lips are moving; they are usually steering, shifting, talking on the CB, talking on a cell phone and trying to drink Mountain Dew, all at the same time. He was obviously having trouble holding cell phone while doing everything else. So he bought the headset, and it works great for while he's in the truck. But he doesn't ever wear it outside the truck. Because he knows that he looks like an idiot if he is standing in line at the convenience store buying more Mountain Dew with the headset stuck in his ear.
Ok, I'm done with my .