That remind me of how Rarity forced Sweetie Bell to haul 5 tons equipment on a camp trip, I am more then sure that Rarity did it as payback for manipulating her into coming on camp trip in the first place, but in most of episode Rarity acted like a spoiled slave driver, but the way how Sweetie Belle was doing all that horrible labour with smile on her face, I must say that her devotion is incredible.