Definitely agree with the moments mentioned so far! The dancing lessons in the movies is such a funny and memorable scene

And I love the interactions between Umbridge and the other professors, but especially McGonagall, in both the book and movie. In particular, the scene in the book when Umbridge is being chased from the school, and McGonagall indicates she would help if Peeves hadn't taken her walking stick
I also enjoy just about any scene with Gilderoy Lockhart. His arrogance and obvious incompetence and the other characters' reactions to him are just so fun to read about/watch.