Question about Hero Story Structure

I was thinking in class about the hero story structure. I thought of pretty much all adventure movies and the all follow those guidelines. Harry Potter, The Lord of the Rings, the movie I'm watching now, Gone in 60 seconds, and lots of other movies. They all have the same basic structure. But what I don't understand is why people, including myself, like to watch new movies if they have the same structure. I don't really get it. Just because the characters change and the complications change it is more interesting. If they all follow the same structure, then you should know what is going to happen.
Well, while I was writing this, I think that I answered my own question. I kept saying the same basic structure. But the change in the characters and plot make it more interesting. But the thing that makes the stories seem interesting everytime is the small deviations in the resolution and climax. Those are the things that make the stories always seem interesting. that and big explosions and guns.