I've always wondered if the guy has some kind of low grade autism or Asperger's Syndrome. His concrete and irrational thinking when it comes to things like eating habits also would seem to support this, as does the way he rattles off "facts" about television. Anyone else ever wonder about that?
A serious answer. Asperger/Autism and any other syndrome. All people have a bit of all of these different trades. John is strange. But he don't have Aspergers since he understands how other people thinks. I personally thinks his strange habits and irrational thinking is because of a strange upbringing. If he was a pure jew, it would have been easy because of the inbreeding within the tribe. Maybe John is from the south where inbreeding also is common.
Oh, a serious answer? He's from Pittsburgh. A lot of people from Pittsburgh are idiots. Must be the water.