"What do you mean that's the wrong way to sew?" Twilight stared at her friend from across the table, eyes wide as she just heard the most horrible words ever.
"I'm sorry, dear, but it's just not... er, oh, what's the word?" Rarity glanced around the room, trying to think of the word to describe the... the... th-the mess in front of her. "It's just not very, erm... 'clean'."
"What do you mean, though? It's clean!" Twilight held up the cloth, showing a sewing job that could only be readily described as 'connect the dots played by somepony having a stroke', the string going from wildly differing points and angles as it tried to hold the two pieces of fabric together.
How she even managed to get one of the ends all the way to the corner when my sewing machine doesn't reach that far... Rarity quickly shook the thought out of her head, holding up her own fabric. As opposed to the purple fabric with red cloth thread Twilight used, in Rarity's magic sat two pieces of aquamarine, held together by a rather nice shade of green along the middle. The stitching was tight, concise, and repeated without error; perfection. "Compare the two, would you, dear?"
"They're both sewed together, though yours is a lot closer together. But you wasted a lot of thread! I, however, chose the best structural points in both pieces of fabric and created a plan." Twilight grinned as she turned the fabric in her magic. Sure enough, the fabric held together and never separated a millimetre, no matter how she held it or pulled. "I saved thirty percent more thread by following this method."
"Twilight, sewing isn't all about numbers, you realize. It's about cleanliness, how well you can sew together two pieces of fabric..." Rarity rotated her own fabric in the air, the thread seeming to be lost in the fabric. "While making it look like it were one piece all along."
"But when you use up so much thread, you have to buy more. What's the point of 'cleanliness' when it doesn't suit demand?" Twilight crossed her forelegs and leaned back in her chair, staring at the dressmaker. "When you sew it like this, you get the exact same holding strength as that job, plus, you get an interesting design."
Oh, what effort Rarity put into not saying it looked like it was done by a three year old. It could be heard in her grinding teeth as she took a deep breath to calm herself. "I realize this, Twilight, but it's not about 'strength'. Look around you. Do any of these dresses have clear seams or thread sewing?"
Following her request, though moreso to find a very obvious reason to prove her wrong, Twilight looked around at the myriad of colorful dresses, gowns, suits and other garments meant to be worn by the wealthy and noble. All the colors blended together from purples, to blues, from oranges to reds, perfect gradiants held together by invisible forces to the naked eye. "Well... no, I can't."
"And how do these clothes lo—"
"Wait!" Twilight suddenly vanished in a blast of light, popping up next to one of the dresses in the corner. She moved around the mannequin, inspecting every curve and crest of the clothing, narrowing her eyes. After a thorough search, a magnifying glass suddenly warped in front of Twilight, and she used it to carry out the search again. "Waaaaait."
"What?" Rarity's eyes suddenly went wide. One of her dresses wasn't perfect? "What? What is it? Tell me!" She teleported over to Twilight's side, warping in her own magnifying glass and joining in the inspection. "What could possibly be wrong with this!?"
"I know I saw something..." Twilight squinted her eyes a little more, tongue stuck out in concentration. The glass moved painfully slow, allowing her full view of the closest details of the clothing. She could see the threads and how they crissed and crossed to create the patterns, the fabric itself... see into the very structure that made up the dress. It was like staring into a whole new world; every single little strand, and how they all fit together with the rest to create the lightest of silks or the heaviest of cottons, each one changing color just a little bit to create a flow of vibrance that she could rarely find in most magics.
The sight almost brought a tear to her eye. Wow... it's... this is like staring at the cells of a living being. Just seeing how everything all combines together to create something so much bigger... yet it's all invisible. Seamless. Her scan drifted to simply take in the sight, until she eventually found the offender; a single, out of place thread that had snapped. "Found it."
The thread was suddenly yanked out by a blue aura, and placed under Rarity's hateful glare. "Ohhh. I always have trouble with this kind of ribbon..." She shook her head and wound the tiny thread up into a ball before chucking it away. "There. No more problems, right?"
"Well..." Twilight looked over at her, before looking back at the dress. Sure, the surface is perfect, but... it feels weird. That hole's always gonna be there now. She looked down at her own leg where the ribbon fell. ...Like ripping a set of cells out of something.
"Hm? Is something the matter, Twilight?" Rarity leaned into her sight, raising a concerned eyebrow.
"Huh? Oh, uh, no. Dress is perfect now, Rarity, and... yeah, I see your point." She offered a kind smile to Rarity, which was quickly returned by a nod of the head and a smile, though it seemed a bit more self-righteous than usual.
"Very well. Shall we return to your lesson?"
"Sure." With a last nod from Twilight, the two headed back to the table, though she couldn't keep her eyes off the dress. Her eyes went back to her leg as a feeling of... emptiness came over her. Just ripping out a thread like that... it did its job as best it could, didn't it? Shouldn't be be handled more... fairly? Maybe tied back into the dress, rather than torn out and thrown aside like garbage?
She wouldn't quite escape from that mental dillema for the day...