Fluttershy: They're unplanned guests. Your woooorst nightmare. You don't have enough food for them! Oh, no! There's a tiny kitten that needs a home! But you are over-scheduled right now. You don't have time to help! I said, "You don't have time to help!" This should appear to scare you! Why don't you look terrified? You showed up to a party and everypony was extremely disappointed in you. Can you imagine anything more upsetting?