Harry Potter and the Deathly Hallows part 1 started off as a fairly good adaptation of the books. So much so it got me falsely optimistic that they would be able to keep it up right to the end. However, they dropped the ball right at the end of the movie.
You know the scene in The Good, The Bad, and The Ugly where they have a mexican standoff? Guess what, the book ends with a standoff between Voldemort and Harry Potter with the entire wizarding world watching, only instead of guns, they're using wands. But NO, the idiot director had to throw out all of the previous goodwill and make the final battle longer and more action-packed and lacking in any meaning or subtlety. Disgusting.
WB always screws things up. They screwed up Green Lantern (though its not as bad as people accuse it of being) and they screwed up Harry Potter. They still made tons of money, but imagine if they got the right director and stayed hands off like they seem to do with Christopher Nolan. They'd have more inceptions and Dark Knights and less turds.