Recently I'd had a thought. My OC and his family are normally the well-to-do family. Kind, considerate and respectful. But with the flak they cop from the other pure-bred unicorn families Canterlot for having an "oddity" born into their family, Steadfast (the oldest, Earth Pony). Eventually they're just going to snap and deal the same amount of pain onto the other families that they received. And this is what came from that idea.
Years of bottled up anger can finally be released and if a family wronged them in the past, then that family won't exist by the next sunrise.