How can we use the article "a" in front of words like "hello" and "thank-you" with or without quotation marks? If it has quotation marks around it, I take it as being treated as sort of an uncountable noun, but sometimes, I don't see quotation marks; then, how should I take it, a normal phrase pattern or not-so-normal one?

Can we put the infinite article "a" or "an" in front of any words in quotation marks?

Dear Joe,

A "hello" you said to my sister for her promotion was well received. She expressed her gratitude for your gracious "hello."

But a "let's get to know each other better" wasn't quite receptive. Sorry.

Your friend,

I'd suggest the quotation marks for the longer, less common greetings, but thank-you at least is a countable noun in its own right (see [url=http://dictionary.reference.com/search?q=thank+you&r=66 ]HERE[/url]) and needs none.
Students: Are you brave enough to let our tutors analyse your pronunciation?
Thank you, Mr. M. How would assess the validity of this use of the articlce "a"? An instance of/example of "let's get to know each other better"? Unlikely it seems. I would be nodding my head for agreement if a decision time for the use of the article "a" for "a 'thank-you' or 'hello' an an example of either of them or an instance of saying "hello" came but something as elaborate as "let's get to know each other better"????

Come to think of it, I think you can say/make just about anything as an instance of it?

An instance of saying "let's get to know each other better" wasn't quite receptive. Sorry.

This making of an instance of something as long and trifle as the above seems to simple to be true. Is my conjecture have any firm basis?

sir it me joe my family is scard plz stop i am calling the cops