Bluetooth Headsets: What Not to Wear

Why do people wear these stupid things? They look so ridiculous, like some prototype cyborg gone wrong.

I'm walking through the town centre and there's some guy walking towards me. He's obviously insane since he's talking to himself, gesturing wildly as he does so. I'm debating whether or not to cross the road, to avoid him, when he turns slightly and the aspect change reveals a mechanical appendage growing from his ear - the Bluetooth headset.

I can relax a little, he's no threat to me. He's thoroughly engrossed in a conversation he's sharing with an invisible partner and doesn't even notice me as our paths cross.

Has he ever looked in the mirror whilst wearing that device? Does he not appreciate just how daft he looks?