Yeah there is definitely something happening during Part II the first time you see it. I remember watching it and liking it and actually falling asleep mid-way through. Then for some reason I woke up after about 5 minutes and kept my eyes glued to the screen for the rest of the movie.

I think the viewer sees that these movies are bigger and deeper than they initially thought mid-way through Part II.

I remember that feeling....

And Part III gets a bad wrap. People here say it all the time. Sure it has flaws but is an awesome and powerful conclusion to a great trilogy.