from net article on Ten Most Annoying Smartphone habits,
Bluetooth, or Crazy Person?
OK, we admit it. If you have just the right fashion sense to go with it, your Bluetooth can make you look like an awesome sci-fi movie cyborg.
But remember, to half of the world, you just look like you're jabbering away to no one in particular.
If you're walking, it makes it awful hard to tell the difference between you and a raving homeless person. And if you're sitting next to us, say in a restaurant or on the subway, listening to you have a one-way conversation into the void is just annoying.
No Bluetooth headset required so most folks assume I am talking to myself when in some cases is a good thing.