Actually, on that point...
The set up was that Miliband asked Cameron a series of "questions" that took as their premise the idea that Cameron was cowardly, lazy and generally useless. He framed these questions by mockingly reading out a series of aspirations Cameron had had before entering Government, pausing for mocking laughter from his backbenchers.
He then said, after Cameron's response, in effect "oooh, he's going red!" We all then score the exchange as to how well each side is considered to have done.
I'm not singling Miliband out here (this is what PMQs is, and what it's now for), but there's really only one other scenario where I can envisage this sort of exchange taking place, and it's a school playground. Danny Finkelstein has a very good article in the Times this morning about, effectively, the death of respect in politics in the United States (short version: Nixon's fault). I suspect that any attempt to argue for respect in British politics would be a pompous waste of time, but it is all awfully weird.