I posted this in the thread from Friday, but think it's worth mentioning again - if you listen to the last few minutes, starting with where Dan mentions the t-shirts, it seems like John was offended by the jokes made at his expense (e.g. not wearing a shirt). Maybe it was the kind of thing that had been accumulating, as I know Dan has made offhand cracks in the past, and perhaps this was the last straw. I believe John felt disrespected/unappreciated, for the last time it seems.