I felt some very strong, gay rights undertones in this short. They are there. Look for them. Pixar tried to cover it up with the woman on the beach scene, but adults can see past this. This is a short film about acceptance, and in this generation, the biggest issue with acceptance is amongst the gay community. Notice how both "day" and "night" seem equally masculine/femanine. What a coincidence. Of course I am open to other theories.
As a gay man this was my initial interpretation of the film, and towards the end I felt almost certain this was the concept.
We all know how smart PIXAR is. They did not sit down at a desk and say "let's make a short film about acceptance" and leave it at that. Acceptance of what? Differences? What kind of differences? How does this relate today? What issues do we have today that have anything to do with accepting people for who they are and who they love?
Gosh. I really wonder, but I'll be child friendly and shy away from the dreaded "G" word.