On TV shows of the B&W era (e.g. Perry Mason) the hero often visits another persons office and two are antagonistic. Then the phone rings, the person answers, and says to the hero "It's for you". I don't recall any case where the person refused to give the hero the phone. I only remember one instance where the person complained before giving the hero the phone.
Another familiar scene is that the hero is at a person's office. The two are anatgonistic. The hero asks to use the persons phone. The person almost always lets the hero do it.
Was that courtesy with telephones actually ingrained in people in those days? Or is the TV portrayal just something to make the plot move along smoothly?