WHY ARE YOU SMILING

I usually don't but here's why I am
  1. I'm being paid to
  2. I thought of something funny
  3. My mouth hurts
  4. The sun is on my face
    Literally and/or figuratively
  5. I'm happy to be with you
    It makes me feel ok inside
  6. I'm wearing two layers of spanx
    I'm actually grimacing