Saw this a week ago, and I can't divorce myself from my relationship with the books and the characters. Specifically, Harry Potter has followed my love life for ten years, and is firmly ingrained in my memory.
I read the first book in the spring of 2001, as I borrowed it from my junior year girlfriend and prom date. I saw the first movie with another girlfriend, the second movie with yet another girlfriend (we got in a big fight after the movie because she seemed unnaturally upset that Harry only wins with the help of his friends), and the third through sixth movies with my ex-wife. Both parts of Deathly Hallows have been viewed with my current girlfriend. Let's hope the boy who lived isn't bad luck on my love life!
As for the last film, I didn't cry but I got goosebumps. I hadn't read the last book in four years so I felt enough distance to not be bothered by any changes. There's actually three factors here: having read all the books over ten years, seen the movies over ten years, and watched the actors grow up over ten years. It's lame, but I watched these kids grow up and every time they would pop up on screen it was like seeing old friends.
I started to realize halfway through the movie that there were faces I hadn't seen yet. Neville gets a grand appearance, but I'm such a sucker that the totally uneventful intro of Hagrid gets a pass. That's why I can't divorce myself from my outside experiences: the filmmakers were aware that the economy of adapting a mammoth book depended on relying on goodwill from both the earlier movies (and books, for the initiated).
Never mind that Cho shows up after not having been in the sixth movie, after she was damned as a traitor at the end of Order of the Phoenix. I'm just happy to see her! Seamus is a pyro? Right, he blew himself up in the first movie.
I know there was bad filmmaking on display here. Ending the sixth movie with the mystery of RAB, only to have him turn out to be a brother of Sirius without any motivation is just bad screenwriting (wasn't particularly great in the book, but at least RAB could be given some description and backstory), especially since the amulet turned out to be a fake and they had to find the real one anyway. Doesn't matter, I was along for the ride.
I'd also note that the addictive nature of this series is insidious. Watching one movie can only lend itself to watching the next, and the next, and by the time you've gotten to the end you forget details and want to go back and watch the early ones. By that same token, what film series can get away with two mediocre movies that will forever be watched with the caveat of "don't worry the movies get better, but you still need to watch them for the backstory!"
Just deliciously evil.