I know what you're thinking and I am going to let this go - until the next study comes out at least, but I had this thought a few days ago.  I even made myself a little list - so I am going to share it.. a nice short post!

In America and many other places, we sit for at least the following activities and feel free to add more in the comments section.

We sit in our cars, buses, and planes as we travel.
We sit in our cars, just to sit, which I never understood and also we stay in our cars to pick up our mail, do our banking, buy our food at fast food joints and even sometimes at the grocery store!
We sit waiting to sit on a plane.
We sit when we eat.
We sit waiting for a table when we go to a restaurant (after we sat in the car to get there).
We sit to play games (like cards, board games and videos).
We sit at casinos.
We sit to be entertained (at the movies, theater and clubs).
We sit when we entertain (have a drinks and such).
We sit when we work.
We sit when we study, at home and in class.
We sit to rest from all our sitting.

Now I do use the word We loosely.  As not everyone always sits or sits for all of these things. I am certainly a non sitter - for instance, I am standing up and typing this sentence right now!  I did sit down for dinner and while at work/school I sat at my desk, but I ate my lunch standing up (today).  I sat down for my transportation - but I was on my bicycle and I stood up to climb hills :)