Kan or Kant Be Overwhelmed By Love

Why does John show false emotion in Marley and Me?  This is bothersome.  He acts as if experiencing the sublime through the death of his dog.  The death of his dog is saddening, but far from overwhelming, far from John's portrayed emotions.  John seems to be overwhelmed by the death of his dog, but only things like violent storms or massive buildings can spark these emotions.  Things that one cannot rap his/her head around.  This IS something he can rap his head around, as death is common in every living thing, and there is nothing new or surprising to that.