Most Unprincesslike

"Simply unbelievable!" Celestia scoffed, pacing across the castle courtyard furiously, looking across at the picnic tables and balloons decorating the castle in a brilliantly colorful spectrum. The courtyard was mostly empty now, the hundreds of ponies replaced with a dozen royal assistants cleaning up after the afternoon's banquet.

"Forgive me, sister, but, I think you may be overreacting-"

"In plain sight! As if I wasn't even there!" Celestia exploded, ignoring her sister. "I never would have guessed it from Twilight Sparkle, of all ponies in Equestria."

"Celestia, please, just wait a minute and look at things-"

"This sort of improper royal etiquette is exactly what I feared she might develop after living a life amongst commoners!"

Princess Luna sighed irritably, loud enough to make the royal assistants across the courtyard look up from their cleaning. It was not, however, loud enough to break Celestia's rambling.

"Before, she never would have commit a crime of this magnitude. Do you know what this means, Luna?" Celestia whipped around to look at her sister, who face-hoofed and crossed the courtyard.

"That we'll need to get another chocolate cake?"

"It means that Twilight Sparkle is beginning to abuse her position of authority, attempting to overthrow us from our throne!"

Princess Luna gawked at Celestia in disbelief. "What in Equestria are you talking about, Celestia... For the last time, it is CAKE!"

Celestia laughed loudly. "Oh, sure, it's just cake now, but then what?"

Luna sighed audibly again. "Oh, yes, I see your point, Celestia." She asserted sarcastically. "First its eating the last slice of cake at the royal picnic, then, oh, who knows...world domination!"

"Precisely!" Celestia screamed, evidently choosing not to acknowledge the blatant mocking tone in her sister's annoyed response. "We can't take any chances! Before, Twilight Sparkle would never have thought to blatantly defy me...but now! Now she has signaled her desire for control!"

"Celestia!" Princess Luna screamed back, her anger building up at her sisters ridiculousness. "You are being utterly paranoid! If the cake means so much to you, I can have the cooks make you one up swiftly..."

"The cake matters not to me, Luna." Celestia replied coldly. "What matters to me, is the fact that she would not even think to leave a piece for her dear mentor! She always has. Did you know that some ancient civilizations offered sacrifice to their gods for well being? I don't ask for much here in Equestria...I ask for just a small bit of respect, especially from my most faithful of students! This is betrayal!"

Princess Luna cursed herself for sending Celestia off into another of her tangents. It wouldn't be easy to get her out of this one. Still, she tried.

"For the love of Equestria, Tia...just calm yourself! If you are this concerned about Twilight Sparkle's status as a Princess, perhaps the best thing to do-"

Luna stopped when she saw that she was talking to absolutely no one, her sister had continued her rapid pacing through the lines of picnic tables.

"Good heavens..." Luna muttered to herself as she pursued her obnoxious sister. "At least it was quiet on the moon..."

...most unprincesslike indeed!" Celestia was ranting. "I don't seem to recall Princess Cadence ever behaving this way at royal banquets!"

"Celestia..." Luna began, quietly at first. Celestia was too engrossed in her own personal conflict, and refused to be interrupted.

"...in every other manner, simply trying her hardest to appear..."

"Celestia!"  She repeated, shouting now. Still nothing. Princess Luna could see she was going to have to roll in the big guns.

"PRINCESS CELESTIA!" She screamed in her Royal Canterlot Voice. Celestia was certainly looking at her now, as was half of Canterlot. "DO YOU WISH TO CARRY ON INTERRUPTING YOUR SISTER, OR CAN I SPEAK FOR BUT A SECOND?"

Every single one of the royal assistants cleaning up after the banquet turned to stare at Princess Luna, who grinned sheepishly in an attempt to kill off some of the terror she had unwillingly produced.

"Of course, Luna. Go ahead. Nopony's stopping you..." Celestia replied softly. "No need to overreact so much..."

Luna tried her hardest not to fly into another Nightmare Moon-esque rage as she spoke again, this time in her normal voice. She could see that she and Celestia had a full audience now, and the last thing Luna wanted was to look like SHE was the one out of line here. So she proceeded with caution.

"You are condemning your most faithful and loyal subject, and now your sister in royalty, for a mundane and ridiculous reason. When it becomes obvious that Twilight Sparkle wants to "overthrow your throne" then by all means, we shall take action, but there is no crime in eating the last slice of chocolate cake. So just calm down, Celestia, and forget about it. Please."

Celestia remained quiet for a long time, and Luna could tell she was thinking of a clever retort to her sister's impeccable logic. Before she could say anything, however, one of the assistants who had been watching the discourse ever since Luna's Canterlot Voice, piped up nervously.

"Umm...your majesty...did you mention...chocolate cake?"

Celestia and Luna both stared at the royal assistant, dumbfounded, as he crossed the courtyard towards them. Hovering in an aura of magic above him was a large rectangular box, which he placed on a table with great care.

"I believe there is a note on the inside, your majesty." He said, shuffling nervously. "I was told to wait until after the banquet to deliver it..."

The two pony princesses nodded in understanding, and Princess Luna used her magic to open the box a small crack, small enough for only her to see the contents. Celestia grew impatient when she saw the large grin on her sisters face.

"What? What is it? Pray tell, Luna!"

Luna continued to grin as she withdrew the note from the box.

"Dear Princess Celestia." She read happily. "I would like to formally put in writing how much I am thankful that you were kind enough to invite me and my friends to your royal banquet."

"Yes, yes!" Celestia cut in peevishly. "Can we skip the formalities?"

Luna cast a glance at her sister, before continuing to read from the note.

"Pinkie Pie was so happy to be invited to your banquet that she cooked this for you! I decided it would be best to wait until all the guests had left to have this delivered...I couldn't possibly expect you to want to share such a decadent treat amongst so many ponies!"

Luna finished reading, passing Twilight Sparkle's note and package to Celestia using her magic. Celestia was completely speechless as she took them, opening the box to see its contents. Luna turned from her and walked across the courtyard, wearing a satisfied smile.

"...Simply..." Celestia stuttered dejectedly.

"Yes, sister?" Luna snickered.

"Simply...unbelievable..." Celestia finished, staring at the chocolate cake in complete shock.