Sweet Apple Acres was an institution grounded in it's history and tradition. The practices of the first settlers were still used, little modified from their origination.
Twilight Sparkle had a mixed relationship with tradition. On the one hand, she benefited greatly as a member of the ancient and revered alicorn monarchy, rooted in the foundation of the Equestrian state. On the other hand (what are hands?), she was intelligent and prescient enough to see that the tide of modernity had already completely invalidated a great deal of pony heritage.
Of course, Twilight was thinking about absolutely none of this as she stepped outside of her Library of Solitude that morning, to investigate some great commotion. "What the hay in going on out here?" She asked the ponies fleeing in terror from something on the other side of the town. Ponyvillians are quite fond of their fleeing and of their terror.
"It's a stampeede!" One pony stopped long enough to say.
"Yes I can see that, but what are you stampeding away from?" Twilight asked to nopony in particular. She teleported to the edge of town. A large cloud of dust defined the trailing edge of a massive herd of approaching cows.
"The cows are invading? I'll put a stop to this!?" She began to cast the spell she had prepared for this very occasion: The Beefvaporation Spell.
“Twilight! Wait!” A familiar yell halted her mid cast. Twilight turned to see who but another alicorn Twilight.
New Twilight was slightly frazzled and dirty, but otherwise identical to the old.
“Don’t murder all the cows Twilight! You set off a chair reaction of events that lasts for decades and ruins everything you love!” New Twilight yelled.
“So it ruins nothing?” Old Twilight asked.
New Twilight scowled. “Our marriage? Did you forget about that?”
Old Twilight sighed. “No I didn’t... Man, I bet Luna was pretty upset about our genocide of bovinekind.”
New Twilight shrugged. “I don’t actually know. You see, when New Twilight came back to warn me, I killed the cows anyway. I don't know why. I just kinda felt like it. That was, like, two minutes ago.”
"And you fugured if there was a real problem you could just escape to another timeline to escape consequences." Old Twilight glanced towards the approaching horde of cows, weighing her options. With a sigh she turned away. “I guess this makes me the more responsible of us two.”
New Twilight nodded approvingly. They both watched as Applejack Deus Ex Machina’d onto the scene and saved Ponyville. They stood in the back as the town emerged to laud their cowpony savior.
“I don’t see why nopony is praising me.” Old Twilight said. “It was just as hard for me not to murder them as it was for Applejack to steer them away.”
New Twilight nodded. “It’s the cross we bear.”
Old Twilight stood silently for a moment. “Are you supposed to disappear or something, now that your alternate dimension is gone?”
New Twilight shrugged. “I dunno. I don’t suppose I could stay?”
Old Twilight shook her head. “Hella no. This is my turf.”
New Twilight nodded in concession. “I’ll be going then.” She took two steps forward. “Unless..” She whipped back around, eyes murderous and horn charged. “I take your place-”
New Twilight exploded into purple mist as Old Twilight hit her with a magical burst.
“So ends that annoying naming convention.” Said Twilight, brushing the remnants of her dimensional clone off of her pelt.
She proceeded back to the treehome, and remained inside for the remainder of the week.