Tear Jerker / The MLP Loops

• Twilight's reaction after going through a Past Sins Loop, and then waking up in a new Loop sans Nyx, showcasing exactly why the Loopers can't have children. Fortunately, Nyx starts Looping that very Loop, shaking Twilight out of her funk.
• Loop 25.10: Twilight explaining the dark side of being a Looper to Gilda.
  "You'll find this out yourself, but imagine everyone around you had a disease. They remember everything up to a certain day. After that, they can't keep a new memory past a full day. They just keep forgetting and reliving the same day, over and over again. Only you remember and grow."
  "How long before you stopped seeing them as friends out of frustration? How many days till you stopped seeing them as people at all? How many weeks till you started meddling, manipulating them for what is 'best'? How many months till you started smashing them in frustration that they can't bucking remember anything?!"
  Twilight stopped, closed her eyes, and breathed deeply, pushing away with a forelimb several times before continuing. "I think that is the root of a lot of madness among Loopers. Offer Dash nothing? Gilda, she has hope of seeing her friend now, not an endless parade of someone wearing your face that can't remember the real her anymore."
• Chrysalis' situation, having started Looping after being Happily Married to Shining Armor during the Slavequestria Loop, she's lost the pony she loved forever. And then she starts Looping, and realises she really did invade Equestria in her baseline.
• Loop 162.18: Diamond Tiara reacting to an expansion giving her Spoiled Rich for a mother.
  Diamond Tiara: It's just... Twilight did warn me, but I didn't... I didn't want to believe it. I mean, before she could be dead, or divorced, or -or whatever, and I didn't like it, but I treasured... I treasured the times we had together, the Loops where she still existed. I liked my mother, no matter who she was, because... because luck of the draw meant she was usually, you know, a mother. And now... and now I have Spoiled Rich, and she's... she's what made my baseline self so... you know. And the thing is, I look at her and... I don't know. I don't feel like she's my mother. Not like the ones I had before, you know? She's... I don't...