David and Dan are too full of themselves and often make wrong interpretations / straight up mistakes / let their own view affect the story in a bad way. I understand the need to change things in an adaptation, but in season 3 they do not care and they change things they could easily keep (Brienne and Jaime being rather evenly matched rather than Brienne crushing Jaime, for instance) and there's hardly any actual scenes from the book - the Queen of Thorns scene (which was great) is the only one up until now. I can see the show going downhill soon, especially if they keep including useless scenes like last week's brothel Pod scene.
On a more positive sidenote, has anyone seen this? http://www.youtube.com/watch?v=jsTVnZm9hFg
Personally, I don't believe it (I don't think the show writers are that clever), it's not in the books (Talisa is made up by the show) so I can't be sure.