I said ‘you kind of look like a duck the way this image is cropped,’ your majesty.

Still probably the single scariest clip of Celestia out there  
(not even counting Daybreaker, who comes across as too hammy anyway).  
@Prof.NightJack  
It was a slow and quiet ‘what’, but also a frighteningly intense ‘what’.

“I BEG THY PARDON?!”

@Background Pony #3D60  
Dude exclamation is not the same exact same as an exclamation point, it has a few more uses then just for an exclamation.
 
A sentence ending in an exclamation mark may be an exclamation (such as “Wow!”, “Boo!”), or an imperative (“Stop!”), or may indicate astonishment or surprise: “They were the footprints of a gigantic hound!” Exclamation marks are occasionally placed mid-sentence with a function similar to a comma, for dramatic effect, although this usage is obsolescent: “On the walk, oh! there was a frightful noise.”
 
Informally, exclamation marks may be repeated for additional emphasis (“That’s great!!!”), but this practice is generally considered unacceptable in formal prose.
 
The exclamation mark is sometimes used in conjunction with the question mark. This can be in protest or astonishment (“Out of all places, the squatter-camp?!”); a few writers replace this with a single, nonstandard punctuation mark, the interrobang, which is the combination of a question mark and an exclamation mark.
 
Overly frequent use of the exclamation mark is generally considered poor writing, for it distracts the reader and devalues the mark’s significance.
 
“Cut out all these exclamation points…An exclamation point is like laughing at your own joke.”
 
— F. Scott Fitzgerald
 
Some authors, however, most notably Tom Wolfe and Madison Acampora, are known for unashamedly liberal use of the exclamation mark. In comic books, the very frequent use of exclamation mark is common—see Comics, below.
 
For information on the use of spaces after an exclamation mark, see the discussion of spacing after a full stop.
 
Several studies have shown that women use exclamation marks more than men do, and one study suggests that, in addition to other usage, exclamation marks may also function as markers of friendly interaction, for example, by making “Hi!” or “Good luck!” seem friendlier than simply “Hi.” or “Good luck.” (with periods).
 
In English writing and often subtitles, a (!) symbol (an exclamation mark within parentheses) implies that a character has made an obviously sarcastic comment e.g.: “Ooh, a sarcasm detector. That’s a really useful invention(!)” It also is used to indicate surprise at one’s own experience or statement.
 
 
So no, it’s not wrong.

@Prof.NightJack  
It wasn’t high volume in the episode, it was a very flat “What.” Menacing, yes, but it wasn’t an exclamation. And just to get it out of the way because these things always turn into stupid arguments about how people define things in their heads rather than what the words actually mean, from Google:
 
“ex·cla·ma·tion  
ekskləˈmāSH(ə)n  
noun  
a sudden cry or remark, especially expressing surprise, anger, or pain.”
 
That’s what indicates an exclamatory sentence! And that’s an exclamation point, the symbol used to denote an exclamation, AKA not the appropriate symbol for use in the image. Because how fast something has been said is, in fact, what indicates whether or not it should have one. If it isn’t sudden or loud or ‘sharp’ then it doesn’t get one.
 
And just to double-check our work, Dictionary.com says:
 
the act of exclaiming; outcry; loud complaint or protest:  
The speech was continually interrupted by rude exclamations.  
2.  
an interjection.  
3.  
Rhetoric. ecphonesis.
 
Hrm, let’s see what exclaiming means…
 
verb (used without object)  

Celestia: I’m thousands of years old. What am I looking at?

Damn, 7 megabytes. That’s massive.

Celestia is displeased.

This part made me feel like Tia and Lulu were Yellow and Blue Diamond…
 
In fact, I can imagine Nicole Oliver singing ‘What’s The Use Of Feeling Blue?’

@IceKitsune  
I think that is a bit much, more she was thinking “shhiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiittt!”

I bet you the only thing that Starlight could think at this point was “I’m soooo going to the deepest darkest jail forever.”

@pwingbrony  
Glim Glam was one misspoken reply away from an extended mooncation.

I legitimately shuddered at this moment. Not gonna lie.

@Background Pony #3D60  
They are used to indicate high volume or strong feeling in how it is said, not how fast it is said.  
So it’s not too slow for one.

Li’l too slow for an exclamation point.