Talking to a passenger can be dangerous, particularly one who doesn't hold a driving licence.

They almost demand answers and it is not always safe to respond immediately. I sometimes have to shut up mid sentence, as a passenger, when situations on the road demand. Passengers are not always registering the conditions on the road, which means I am annoyed with myself at the slow realisation.

The person on the other end of the phone has no chance to assess the demands on the driver.