OK, so much for the goody-two-shoes rules.... Online, it's easier and looks better to violate all the rules and just follow your statement by three or four closed-up periods, depending on whether or not you are at the end of the sentence. If you don't close up the periods, HTML will do it for you.

It's called an "ellipsis" (plural: "ellipses"), and it's used when there is a pause or when words have been left out of a sentence. It is also used in the place of words left out of a direct quote.

Examples of the first use:
"I don't know . . . maybe it isn't such a good idea."
"I know that bright colors are fashionable these days, but that dress. . . ."
"So, if you multiply 1/4 by 3/8, the answer is. . . ?"

Second use (quotation):
"I pledge allegiance to the flag of . . . America . . ." (Pledge of Allegiance)
"one nation . . . indivisible, with liberty and justice. . . ."
"What are these things called. . . ?"

Spacing rules:
If used inside a sentence, space between each period and on either side of the ellipsis.
If used at the beginning of a sentence and the excerpt begins with a lower case letter, an ellipsis is not used. But if the excerpt begins with an upper-case letter, it might be confused with the beginning of a sentence, so the ellipsis is used.
If used at the end of a sentence, the ending punctuation is retained and the ellipsis is closed up against the last word of the excerpt.

Never use an ellipsis where a colon should be used. It also isn't necessary to use the ellipsis if it's obvious that you're using just a couple words taken from a sentence (for example, if I was to quote "do you and do you not" from your question).

OK, disregard all that as I did not really answer the question, did I.

As you used it, yes, "essence" should be singular, because it is a single essence shared by both things. "Color" is another good example. "The color of Mallory's hair and Jason's hair was identical."

But there are senses in which you would use "essence" and "color" in the plural, so: "The essences of Spanish lavender and English lavender are identical for the purposes of woud healing." ("Essences" meaning "essential oils.") The colors of her kitchen curtains and her table linens are identical." (More than one color being spoken of here.)

OK, have to stop thinking and start working now :)

OK, back. Relevant examples:

Was:

"...the vertical distribution of heat and particles was identical in megaplume 1..."
"...the number of runs and rewards was identical in both..."
"The definition of variables and outcomes was identical..."
"...the subtyping of gliomas and astrocytomas was identical in all 55 cases..."
"Evolution of starch and sugars was identical in the 4 ripening stages..."

Were:

"The vials of phenol and guanethidine were identical except for the names..."
"..."the original inhabitants and native rulers of the countries of Ethiopia and Egypt were identical..."
"Russia at the time was largely a medieval country, where the worlds of church and state were identical"
"During the night, the values of Tp and Tc were identical..."
"George Sicard's contention that the powers of orders and jurisdiction were identical..."

Obviously wrong:
"The number of peaks and pattern were identical in both cases..."
"...it became evident that the teaching of Hus and Wyclif were identical..."

I think the key is given by the noun that precedes the prepositional "of." If it is singular in form, then the verb is singular also ("was") and if plural, then it also agrees ("were").

Feelings, wo, wo wo, Feelings....

Compare:

"The plots of this book and that book are identical."
"The color of this book and that book is identical."
"The main characters of this book and that book are identical."
"The publisher of this book and that book is identical."

Gee, I don't know what I feel now. I'm off to Google this one.

Most dictionaries define "peeve" as an "annoyance." "Pet" would refer to something that is a favorite of yours (think about the phrase "teacher's pet."). It's meant ironically in this case to mean the same sort of thing as holding a grudge.

The non-idiomatic meaning of the phrase would be something like "favorite complaint." You wouldn't use it for everything--just for something that PARTICULARLY bothers you.

I'm vaguely guessing from the special way the word "pet" is used that the phrase dates from around 1800 or a bit later. Anyone know for sure?

Hmmm. I think "wavy brackets" is the Southern U.S. vernacular. :)

Same in what sense? Are we ever exactly the same from one moment to the next? What is the meaning of life, anyway?

(grin) I may have dropped a few brain cells between one occasion and another. Especially since I've been in meetings for hours and hours watching mouthbreathing secretaries molest the engineering documentation I've spent days writing. Forgive.

Don't forget that the construction "There is too much water here" is also correct and contains "much." "Many waters" is a Biblical usage that I think was intended to translate a passage that actually meant "many bodies of water."

Blend, if we could so easily refer to "any grammar reference book," there wouldn't be any need for this site. Or any fun either. :P

I especially like it that many speakers, of different dialects, can share views here in a living-language sort of way. Don't you?