Better in the book #4 (POA)

Everything involving Sirius. He was too ambiguously evil in the movie, while in the book he came off as more mysterious than evil.

Every. Single. Scene. I'm not sure what happened to Daniel with this movie, but he was always either way too hammy, or too subdued. I didn't buy his performance at all.
Let's just say, I got used to seeing this face:

I actually liked this scene in the movie, but I put it here because they tried too hard to make it funnier than it was.

I swear when they were making this movie, they thought Ginny was a piece of furniture. She only gets one line, and then, she is mysteriously gone. That's a great way to treat Harry's future wife and mother of his children.


I rest my case, this is the only picture from the movie that contained Ginny.

The origin of the marauder's map:
This movie never explains why the marauder's map exists in the first place. This makes peter pettigrew betraying his friends seem like almost nothing. This also creates a problem in the fifth film; Harry callin Sirius Padfoot.
This movie does not explain who Moony, wormtail, Padfoot, and Prongs actually were.

FYI, in this picture, from left to right:
Moony, Padfoot, Wormtail

This movie also fails to explain part of the reason snape protects Harry.
Also, The "subtle" hints that Lupin was a werewolf were not very subtle.

Lupin and Harry's bond is a major aspect of the book, and he becomes sort of a father figure for Harry.

In the movie, he's reduced to being the cool teacher who helps Harry out sometimes.