Politeness - showing respect

There are many ways in which we can show that we value and respect our listener or reader. In more formal situations, we are especially careful to use certain polite phrases:

Addressing the audience

Ladies and gentlemen, please welcome Mr Patrick Murphy …

A waiter in a restaurant

May I take your plate, sir?

A message in a thank-you card

Thank you for your wonderful gift.

Asking a stranger for directions

Excuse me, I’m looking for Cathedral Street.

In formal contexts when we don’t know people and we want to show respect, we use titles such as Mr. + family name, Ms. + family name, sir, madam, doctor (Dr.), professor (Prof.):

Checking out at a hotel reception desk

Here’s your credit card, Mr Watts. Have a safe trip.
Thank you.

At a restaurant

Shall I take your coat, Madam?

Emailing a professor that you don't know

Dear *Prof. Kinsella …