Also it is very ‘honest’ in the way it sets things up from the start and pays them off as the story plays out. To borrow the old speechwriting adage, it tells you what it’s going to tell you; it tells you; and then it tells you what it told you.
There are no cheap twists or unnecessary diversions, and everything in the series revolves pretty tightly around the core that’s there from the beginning. But it also manages to throw up some surprises that are perfectly logical but that you don’t necessarily see coming. It never cheats for the sake of a surprise reversal, everything makes sense given what has gone before.