How they kept Mrs. Weasley’s dialogue from the book during the battle scene
The epic moment when Neville kills Nagini
The special effects with the protection charms around the castle
Ron actually looking like he’s 40 at the end while everyone else looks the same, and it being hilarious
How they managed to fit in Snape’s memories and history in a reasonable amount of time
Snape in general/Alan Rickman
How good Ron & Hermione’s kiss was
How awkward Harry & Ginny’s kiss was–it never gets better
That awkward moment when Voldemort hugs Draco Malfoy
How they cut out the part where Voldemort brags and celebrates more about killing Harry/When Harry doesn’t feel the cruciatus curse
The fact that they didn’t include the explanation about Dumbledore’s past (aka why he had all three deathly hallows items, or how Ariana Dumbledore died) I know it’s not realistic to include every story or plot line from the book in the movie, but there are plenty unnecessary added scenes and slow-moving sections between parts 1 & 2 that we could do without.
Most hated: how understated it was when Harry killed Voldemort.
In the book, everyone in the castle watches, the tension builds as Harry explains about the Elder Wand, then he finally kills Voldemort with it, and we see his body fall to the ground looking satisfyingly weak and feeble. Instead, we got an abandoned outdoor entryway and Voldemort disintegrating somewhat honorably into ash, and not nearly as much celebration afterward.
Added notes after seeing it a second time:
What was up with McGonagall sending the Slytherins to the dungeon??
More annoyed at the lack of recognition that Harry just killed Voldemort. It’s like he turns to ash, nobody sees it happen except Harry, then suddenly everyone is just in the Great Hall cleaning up and chatting away.
The attempt to add humor with Professor McGonagall saying “boom” was kind of awkward. I know they were trying to make it funny because she’s normally so serious, but she seems out of her element the entire movie anyway so it doesn’t feel as surprising to hear her say those things.