Respect the Lore
If there’s one thing that fantasy fans hate, it’s when book adaptations overlook the lore. It may seem obvious that following the original text closely is the best option. However, sometimes, a novel may contain elements that don’t work on screen or too many characters.
A show may condense these or leave them out entirely. This is forgivable but it’s never a good idea to completely change the setting of a place or to make big changes to a storyline. HBO must respect the lore because fans expect it (via Den of Geek).