Cause/Effect Relationships

I'm having trouble deciding if, given a specific example, a relationship is Causation, Common Response, or Confounding. For example:

One Saturday in November, a teacher takes his 21 month old daughter to the OSU-Michigan Game. His daughter seems to be watching the fans more than the game. She notices a high negative correlation in the emotional state of the fans wearing scarlet in relation to the fans wearing blue. As the fans in scarlet are getting happier and happier, the fans in blue are getting sadder and sadder.

Explanitory variable: Increasing happiness of OSU fans (scarlet)
Response variable: Decreasing happiness of Michigan fans (blue)
Lurking Variable: Team which is doing better (OSU)

Relationship: Causation/Common Response/Confounding?

I believe it's Common Response because OSU doing better affects both OSU and Michigan fans, but when it comes to Confounding, i really just don't understand. Could someone try to explain this to me please?

If all fans were polite at all times, this must be a common response to the lurking results on the field. Fans are not always polite.