Driving under influence of… a mobile phone

Why should I?
In most countries talking on a mobile while driving is forbidden by the authorities. Some of them even try to establish penalties heavier than regular tickets (ex. jail) for doing it.
The authorities try to protect us at all costs, forbidding to do the every day stuff – and “mobile” is just one of the examples. This particular ban is one of my (and their) favourites. You’re not allowed to use it on a plane, in the post office, library or at the gas station and in the car. I can understand the post office and library – there is a need of silence there. But for example there is no proof that the electro-magnetic waves influence other machines around.
And is this really so dangerous when in traffic? Picture Yourself driving on a highway and talking on the phone (held in hand). Does it feel as creating danger to the people and cars around? Or is talking something natural, that don’t necessary takes much of Your focus away from the road?
Of course I’m not talking about freaks that go 100 mpg in heavy traffic and still talk – it’s not talking that’s dangerous then.