This might be a bit of a beginner's topic. As with all things, this requires both context and empathy to get the most out of, but I've boiled things down as much as I'm comfortable with.
I'd like to take the time to discuss moments of social transit. How do people enter a conversation, and how do they leave? And how do we do that better?
It's probably important to say that we should be nice (at least) most of the time. But it's also important to say that not every moment is a moment where being polite matters – most conversation is just conversation, it's going well as long as everybody has enough words and nobody has too many. People need more conversation, particularly with strangers and others who might be the most unforgiving about awkwardness. And I've noticed beginnings and endings need more work than most, are the source of a lot of the anxiety people have, and so we might as well start there.
This is all to avoid giving too much credence to the "peak-end rule", which along with most of behavioral economics, should be presumed fragile or non-predictive. Since you don't know what a 'peak' experience could be for someone else, it essentially boils down to saying people walk away from a conversation remembering one thing, and also there's the bit at the end they don't really have to remember, because nothing's happened since then. I suspect some people remember zero things from some conversations, and I've sure had conversations where I've remembered more than one thing. But whatever, lets start handing out Nobel prizes for this stuff. I guess "people mostly remember something" is groundbreaking now.
Of course, in stories, conversations are always so abrupt. No idle chitchat for a minute or two while people wait for everyone to arrive, no complaining about how the weather has impacted you, specifically, in your unique way. People answer the phone to have important things said instantly, not the awkward fishing for information we all need to do to make sure it isn't a robocall.
Don't get me wrong, that would be terribly boring to read, particularly if the entire book is composed on dialogue scenes where this would happen over and over. I can stand to hear stories about how that woman you sort of know from that thing a few months ago, well she was having this obscure trouble in her personally life that she has not been handling well, and we ought to get to business but man, can you believe her? But if that gets repeated over and over throughout a book I would probably blow my brains out. It's too much to put in a loop.
So how should we start a conversation? Cautiously, I suppose. You never know precisely what someone is doing, or if they want to talk with you specifically. Some people strongly suggest confidence (without knowing much about Tony Robbins, let me suggest he would describe it as 'essential', or some similar nonsense), but I think you can have a cautious confidence. If humility means anything at all, it might mean that.
And, at the risk of being too obvious: try and match what people are looking for. You could take some other strategy, like being hilarious in a business meeting, but that's going to have almost precisely the results you'd expect from something fundamentally selfish. It's okay to have the conversation you want instead of the one someone else wants. But understand that you're choosing that. People usually don't want such strange things that catering to them would be a substantial burden.
In business scenarios, sometimes you get people who are extremely zealous in their defense of their time. They skip all pleasantries and procedure, and get down to the work of the day as immediately as possible. It might be prudent to join them, in that story-esque efficiency, even if it makes you slightly uncomfortable – that's a lot of what etiquette is, really, choosing to be uncomfortable to shield others from that burden. But I'd recommend you don't take that communications style voluntarily. I cannot imagine the level of disjoint focus required to make it worthwhile, but if it did, you'd be regularly imposing on others. It's a strange thing, to talk with someone and yet share so little. Work isn't really the nexus of our feelings, which means discussions of it rarely build close relationships. Why choose to do business like that?
Of course, most conversations aren't up to us to set the tone for – they're already in progress. I recommend listening for only long enough to see if you can contribute, and then do so. Tell a joke or help out. See what kind of reaction you get. It's okay to avoid a conversation where you aren't getting a positive reaction. If you're expected to continue, either because of a prompt or because of structure (for business meetings), then maybe use the opportunity to express a general positive attitude. If you suspect you won't be able to be heard, then you ought to make sure people know you're basically doing okay without the conversation. No problems to share in the meeting, no ability to continue in person.
And if you need to exit a conversation without ending it, there are plenty of options. You've gotta go, or someone is waiting for you (a softer version of saying you're needed elsewhere – many spouses wait for their partners even when they aren't needed, it's an inevitable part of cohabitation). Or just have an alarm go off and don't explain any more than "that's my cue to go". It would be a very strange breach of etiquette to even ask for details, so it's pretty general-purpose.
But if you have a specific and good reason, that's probably good to share.
In any piece of etiquette, we should probably imagine at least three things: how we make people feel, how we make them look to other people present, and how we make ourselves look. Being interesting to someone helps with the first, but if it is a broad and inclusive appeal, it helps with the second one too – they want to be seen as inviting to interesting people. It's almost as good as being interesting themselves, because at the end of the day, people who want interesting conversation (most of them, I'd imagine, although so few people spend time preparing to advance that goal).
And here is where I make the obvious statement about self-deprecating humor: it doesn't mean using put-downs against yourself. It means making people uncomfortable to be with you. Acknowledging flaws just shows you're human. Pakalu Papito uses self-deprecating humor (easier when you can play a character), and it makes him uncomfortable to view as a friend. You wouldn't rely on them, you wouldn't trust someone like that, and no one would feel sorry for you if you placed that trust and it was betrayed.
Self-deprecation is bad because it makes you look bad. The humor can be really funny, but I think it's so rare that people ought to be admonished for "bummer-light" humor. Don't be slightly a bummer, even if you can get a cheap laugh out of it.
Eagle-eyed readers will notice a gap in my breakdown of important things to consider in etiquette. How do we make ourselves feel?
I've got no easy answers here, except to suggest that you establish firm boundaries with people around immediately expressing whatever true statements you'd like around this. If someone violates any other boundary of yours, you can use your regular judgment to decide if you should say something. But if you feel you can't say anything about how people impact you, at any moment (but particularly when starting a conversation – an exceptional opportunity for someone to interrupt or be rude), then you've failed in some sense. You need to be able to give people frank and honest feedback, even if you don't always choose to do so. I've had relationships where that's not been the case, and it's been, without exagerration, the most disasterously destructive element of any relationship I've ever had. By the nature of the very problem itself it's hard to solve – what do you do, tell someone, hey, you're impossible to give feedback to, and it's made this relationship dysfunctional? It's both the only thing to do and officially voids the warranty of any rules of etiquette – you're operating without a manual, so I wish you all of the emergency reserves of grace and kindness you could possibly handle.
What should be our goal with all this? Is it merely to leave a good impression? How seriously should we take people who say they wish to be efficient? There are too many people out there that insist on "information-delivery" conversational styles, and eschew rules of etiquette because they appear to waste time (and probably do waste time, on balance, but that effect is swamped by the courteousy given to people who choose to waste time, which can be addressed other ways).
I think the rule of thumb ought to be: if someone is suspending etiquette because they want a more efficient conversation, I think it's fair to ask them, "Do you actually need that higher level of efficiency, or is this merely an affirmative disregard for managing social expectations?" I think that's a phrasing that would probably be okay in a workplace (where most of this comes up, it seems), and if someone is trying to justify being direct to the point of rudeness, you'd imagine they'd allow it.
We should probably be careful around people who are particularly proud of their affirmative disregard for etiquette. Social expectations are important, and not just because they create relative chaos when removed. They also make it harder to exercise empathy and delight other people. And if you don't want to do that, then what's the point of any of this?