Someone took a Wonderbolt that briefly appears in "The Best Night Ever" and built some fanon with her - Echo the blind Wonderbolt. This post puts her in Woobie territory.
Becomes Harsher in Hindsight when Rarity finds herself in the pre-Grimdark world, where everything's back to normal, and realizes she doesn't want it. But in order to get that world back, she realizes she'll have to murder Opal again. She really doesn't hesitate.
Heck, several posts across the blog imply that the Doctor (similar to Pinkamena above) knows what he's become, hates himself for it, but doesn't know how he can ever go back. And despite his protests, he does seem to suffer from incredible loneliness without Derpy by his side.
This post which is what happens when he's given crayons, starts out funny...then deteriorates to this. Of course, one could argue that it's all played for (dark)laughs.
The ongoing drama between the newPinkamena and her..."boyfriend", The Master. Being as obsessed with him as she is, hearing that he might have been cheating on her had quite an effect. So far, it seems that it'll take quite some time for either of them to totally recover.
