Besides that dialog in general in movies/books is very to the point. Small talk is kept to the minimum since its not interesting for the story. Dialog is there to push the story forward, not to fill in gaps between parts of the story.
While I agree with the last sentence, the two others have to be weighed up.
Firstly because small talk offer the best opportunities to dig a bit in the characters' life and personality.
While not strictly important in regard of the story, it's by knowing the characters better that players develop feelings (good or bad) for them and, therefore, that the story itself will catch them.
There's nothing more infuriating than a character that pass its time breaking the action with "wait, before we go, I need to do/say this". Each time it seem that a progress will be made, players will be awaiting her annoying interruption, already grumbling...
Gotcha, you involved them. Not in the best looking way, but you did it, it's more than what half the games available here achieve to do.
Secondly because they add depth, and a sense of living, to the story.
They are showing that the characters have a life behind being involved in the story. They aren't robots, nor are they dummies, and, by then, can be loved, or hated. Books and TV series that really succeed, and that stand the test of time, are precisely the ones that don't focus on their story, but also take the time to give a life to their characters through, among other things, small talks.
Remove small talks from
The Lord of the Rings, and you remove a third of movies content (more if you use the books as reference), while removing three quarter of the interest. Plus, Gimli, Peregrin Took and Meriadoc Brandybuck would be silent 99% of the time.
Thirdly because they help to balance the pace of the story.
As annoying as Miss "wait a minute" can be, it's her who permit to the story to last three hours instead of five minutes. Write her more clumsy than annoying, and she'll because the lever you'll use each time you need to lower the tension.
[Note: Because apparently it need to be said explicitly, these are voluntarily grotesque dialog lines. The goal isn't to be realistic, nor to be 100% accurate, but to give the general tone in order for the reader to understand ; it's an illustration of my saying, not a professorial example.]
"Oh my god ! If the information are true, Doctor madguy will destroy the country in five hours ! Quick, quick, we need to stop it, he live next door, we should have the time !"
"Er... Can you wait a minute ? I need to change my shoes, I just broke my heel."
"God ! Girl, when will you learn to use practical shoes when in mission ?"
While, of course, one shouldn't abuse small talk, they are still an important factor, as well as a perfectly legit narrative lever. It's not them by themselves that are an issue, but the way they are usually used.
Dialog shouldn't be used as an information dump. It's something a lot of games on here does wrong; they over explain to much. The reader doesn't need to know everything. If something isn't important for the story, just leave it out.
And here, it's the opposite, I agree with the starts, and disagree with the end.
Importance is something relative, once again because the story by itself isn't the center of the game/book/movie. It's something important, what link all the elements together and give a purpose to all the actions, but what matters is the characters ; something that apply even more to adult games.
Take
Scooby-Doo by example. The viewer isn't solving a mystery, the viewer isn't at all interested by the mystery. No, the viewer is witnessing a group a teenage friends that are transitioning to adult life. The different mysteries are the reason why the characters are here, but not the reason why the viewers are here.
It's the same for, once again,
The Lord of the Rings. Defeating Sauron is important, and what links the characters together, but the core of the story is the journey, not its goal. It's the reason why Peter Jackson was the first one to succeed while adapting the story into a movie ; he was also the first one to tell the journey and not focus on the sole goal.
Even the breakfast complaint, as useless as the scene can feel, is really important. Two persons, Pippin and Merry, that have nothing to do here, feel and, most of the time, effectively are totally useless, and who are ready to complain about what feel like a pure futility, if not a pure childish whim, will end being the heroes that will spend all their (limited) intellectual capabilities in order to force Ents to join the war.
There's the equivalent of two movies/books in between those two scenes. Yet, without the apparently useless first, the second loses all its meaning.
Anyway thats enough ripping apart somebody ells example (sorry lol)
There's no need to be sorry, because it offer a good introduction for the next point: The importance of context understanding, and the importance of keeping things into their context.
It's something that
GNVE already said when talking about the restaurant scene. The dialog you'll write, and how you'll write them, is strongly dependent on the context.
Whatever the tone or the body language, you are limited in what you can express through them. Therefore, the words will have to convey a bigger part of the information than they usually do. And to achieve this, they need to match the context you have in mind because, from the player point of view, it's them that will define it.
Take Eternum as example; Its to me one of the best writing games on here, since a lot is happening in it.
Oh god... Well, this explain the rest I guess.
