Look at My Face.
When DD sees me looking unhappy, she'll ask, "are you mad?" If I answer "no," her next question is, "why is your face like that?" She's not commenting on some odd configuration of my facial features, but rather why I don't look happy. She'll often say "be happy Mommy," when she knows the unhappy look is the result of some minor offense she has committed.
She turned this around in a very cute way at a store the other day. I was just casually browsing, looking for gift ideas, and since I didn't mind wandering randomly around the store, I let her be in charge of where we were going, and just followed her, except for when something caught my eye. She was enjoying this, until I stopped at what she felt was a time we should have been moving. She turned around, said, "look at my face" (while pointing at her face), and said, "come on, let's go that way!" Apparently I disappointed "the boss." I didn't think quickly enough to say "be happy DD."