This excerpt, also counts as a Tear Jerker, shows what happened during Ponyville's destruction in the Grogar Wars. Very nightmare inducing if you keep thinking of it and the Ponyville we all knew and loved.
Princess Theodora's rule. It was very harsh for non-Zorypontans (a post-Celestia era monotheistic pony religion).
The Grogar Wars. Word of God said that 60% of Equestria's population died during the War. What is left are warlike, cynical and hostile ponies in the Ponyland Confederacy.
They also did it to the Equestrian diplomats' daughter without them knowing since she was born there.
Gipsy's anti-trespassers illusions can be very scary to unsuspecting visitors.
The horrible working conditions in the Jewel Wizard's gem mines were thus:
The slaves were all blinded by long exposure to darkness.
Foals worked too.
The slaves worked non-stop until the fell from exhaustion.
Those too exhausted to work were ripped apart, gutted and eaten by their goblin guards.
The chapter 'Goodbye Equestria. Hello Ponyland' in Applejack Through the Ages describes former Equestria after the two year long Grogar Wars as a vast wasteland full of decaying deceased ponies and ruined cities and villages full of roofless buildings. It also describes the land filled with tired and starving refugees.