Because at a young age you are given a mark that symbolizes what you will do with your life (although 3 smiling flowers does not equal teacher)Nabber said:Why?Plunderbird said:The Cutie Marks concept reminds me of the Giver
EDIT: Also I noticed something in the first episode with Rarity's cat in it the cat was fairly friendly (if not a little stuck up) but by it's next appearance it was very mean to Rarity.