Order of the Phoenix is probably the most angst ridden of the books, and yet it makes perfect sense.

Rowling took to understanding just how imperfect her characters are, and this book goes through the lengths to show it. Harry Potter is dealing with being left out of the dealings with the return of Voldemort. All of the past journeys have piled up within Harry all in this one book.
There really is no wrongs in this book, Rowling continues to expand the wizard universe, her improvements in writing carry on to this book, and the characters are all more real.