Ok, so a million letters have been typed about telephone etiquette.
I have my $0.02 worth.
Literacy or social position doesn’t educate a person. The lady on the train today was a classic example. A senior manager in a well-known organization, she is well-traveled, & is in charge of a fairly large team of people & manages a multi-million dollar budget. How do I know? Well, she practically told the entire compartment during the course of her several conversations on her “smart-phone’! No wonder they call them smart-phones now, the users definitely aren’t!