Applejack was happy for Rarity, she really was. Moving to Canterlot to pursue a rather unique oppurtunity made sense... but it didn't help her feel any less homesick. As Rarity works on special dresses for the biggest fashion show of the season, Applejack dreams of where the fields are, where the summers are wet and the winters clear.
Happy is she who knows the causes of things--and as Rarity begins to understand the underlying problems with Applejack's discontent, perhaps she can find the right words to say.