According to writers David Benioff and D.B. Weiss they can’t afford to specifically write a theme for every episode as is convention on television. In a podcast at Winteriscoming.net Bryan Cogman also commented on his episode (Kissed by Fire S03E05) that they don’t specifically set out to write an episode about certain characters. But he said that it can happen that some scenes in an episode correspond to each other in a way so that it seems as if there was a deliberate theme.
This seemed to be the case with The Bear and the Maiden Fair – the seventh episode of this season – written by no one else than George R.R. Martin himself.