We all know that the Harry Potter franchise got it pretty lucky with its film adaptation. For the most part, the films followed the story and stayed true to the book series. There aren't a ton of memes on how terrible the movies are (I can't say the same about the Percy Jackson movies), so that's generally a good sign. However, as potterheads, one has to admit that the change in a few details had us all mentally raging at the screen in front of us.
What was your least favorite change from the Harry Potter books to the movies? Was it the exclusion of S.P.E.W.? The exclusion of Fred's death? The added attack on the burrow scene? Let me know your opinion in the comments below.
What was my least favorite change?
Cho Chang's Betrayal

In the Order of the Phoenix movie, the DA was turned into Umbridge by Cho Chang under the influence of Veritaserum (the truth potion). In the books, it was Cho's best friend Marietta who betrayed the DA. This "minor" altered fact bothers me for a variety of reasons.
1) This changed fact was used to present a "logical" reason for Harry and Cho to break up. I beg to differ. Cho had told on the DA under the influence of Versitaserum. Considering it was Umbridge who had done it, this could be the equivalent of mental torture and strain on a person's mind. Although Cho had let the group down, this "reason" for her and Harry's breakup make the gryffindor's character slide a bit downhill. Harry isn't very good with relationships, we can all agree on that, but someone who truly loved another person would not break up with their boyfriend/girlfriend just because they snapped under the pressure of a truth serum.
So point one: Cho's betrayal gave Harry Potter a bad characterization point
2) Making Cho antagonist like reinforces the "evil Asian" movie stereotype. Asians get enough hate on the big screen.
That's all I have for my mini-rant session. Let me know if you agree or disagree!
@DailyProphet, I agree that they should have kept Marietta as the one who betrays the DA. It makes the movies leave out the humor of Cho Chang thinking Harry liked Hermione.
@OneSavageSlytherin, I hated that too! My favorite part of GOF was finding out if Harry would complete all the challenges in the maze. And, I thought Dumbledore’s reaction was really funny too!
My top three least favorite changes would be the exclusion of Fred’s death, how they left out Barty Crouch Jr’s backstory at the end of the Goblet of Fire, and how they made the Burrow burn down in their sixth year, yet it’s completly rebuilt without any mention in the seventh year. And that’s only my top three!
Anyway, I think you’ve had enough of my ranting, so that’s the end of my comment!