I hate having to answer the question "what do you think is the most important part of a movie" because it is simply impossible to answer. Every part of a film contributes to how good the final product is. Without good actors, the character's don't seem real; without good writing, the situations don't seem real, and without a good director the whole project falls apart.
However, there is always one part of a film that always stands out to me. One thing that in my eyes that can make or break a film: dialogue. Whether or not the characters have believable banter is what contributes to an entire film feeling realistic or not. That is the particular reason why Judd Apatow and Quentin Tarantino are the best scribes currently working in Hollywood.
I would like to bring up a very recent example of great dialogue. It is a very short scene from "(500) Days of Summer." This snippet of dialogue might not seem like much when read aloud, but when put in the context of the film, it is incredible:
Summer: Is that true?
Tom: Yeah, yeah. He drinks and he sings...
Summer: No, no not Mackenzie. The other thing.
Tom: What thing?
Summer: Do you...like me?
Tom: (Pause) Yeah, yeah of course I like you.
Tom: Right. As friends.
Summer: Just as friends?
Nothing remarkable sounding here. But yet, there is. Even when not hearing this in the context of the film, there is something beautiful about this dialogue's simplicity. In it's simplicity, it feels so real. In it, Summer isn't really asking for an answer she doesn't know, she is just asking for confirmation for something she believes has to be true.
But that's not the point. When you see this scene in the movie, you will realize everything about it is perfect. The surroundings of the scene seem totally irrelevant; everything is focused on Tom and Summer because it is all about them. This is their moment; their first moment where they see that something other than friendship may be possible in the near future.
Gordon-Levitt and Deschanel deliver the dialogue flawlessly. Every emotion they convey is perfectly entwined with every word they speak. They add a level of friendly awkwardness that no script can convey on it's own. It is the true essence of onscreen chemistry: two people (typically a man and a woman) being able to communicate with each other at a realistic level, whether for positive or negative reasons.
I recall a line from Roger Ebert's "Pulp Fiction" review in which he says "this movie would work as an audio book." What he's saying that when dialogue is good, sometimes listening can defeat watching.
Good dialogue is like good music, you can listen to it over and over again. That is the case for this scene of "(500) Days of Summer." It is no complex, witty conversation about hamburgers or foot massages but simply an intimate moment between two strange souls. It is not just the words you want to listen to over and over again, but the delivery.
If "(500) Days of Summer" gets nominated for Best Original Screenplay at the Oscars this year (which I 100% guarantee you, it will), this will be the clip shown when its title is announced.
The next installment of "That One Scene" will discuss the "Ride of the Valkyries" scene in "Apocalypse Now."