You
I'll deal with your issues first: you are an angry 14 year old.
Don't sweat it; everybody was, is or will be. Maturity can in fact be summed up as learning not to punch the face of someone who richly deserves it.
You have to remember that you have no control over the way other people behave; you only have control over the way you behave. And ... you behaved badly. People say "I lost my temper"; this is a euphemism that means they choose to express anger in an aggressive and non-productive way. Learn to choose to react differently; no one ever changed their mind by being yelled at - at best you can get someone to back down and resent you.
Oh, and because none of us is perfect and I have chosen to "express anger in an aggressive and non-productive way" myself (and no doubt will in the future), you need to know how to recover from that. This is easy: it's called an apology. There are 2 reasons we say sorry and both are applicable here: 1. to show that you know that you behaved badly and 2. to repair the hurt you caused other people.
Him
This guy was rude; there is no doubt about that. You haven't mentioned his age or the age of the group but if this guy was an adult then this is really bad behaviour; if there were adults there who didn't intervene then this reflects poorly on them too.
All the stuff I said about you is equally applicable to him; of course, he's not reading it.
Due to the wonderful diversity of humanity you will, from time to time, encounter people who are rude. They may be rude because they are: tired, drunk, just had their dog die, just got fired, have a splitting headache or are just obnoxious p*%^ks who didn't have enough parental discipline growing up. Notwithstanding, dealing with rude people is a skill and, like any other skill, you can learn it.
Here's a quick quiz. In response to his opening remark of "Let's get this over with, I got stuff to do.", which of the following is likely to give the best outcome:
- Ignoring it
- Beating him to death with your dice bag
- "Sorry we're keeping you, why don't you leave now?"
- "I was planning on a 3-4 hour session. What time is your other appointment and we'll see what we can do to accommodate it."
No 2 could be fun but No 4 does a lot with a great deal of economy, it:
- doesn't let the rude remark slide through unremarked
- shows that you care about his problems (both the other appointment and his rudeness)
- establishes expectations on timeframe
- establishes your authority
- enables the group as part of the solution
- shows what a nice guy you are.
Note: even if you say this you don't have to accommodate him! Polite and nice are not the same thing.
Expectations
When you sit down to play chess you know what you are going to get but when you ask someone to play football and you come ready for soccer and they come ready for gridiron; you have a problem. Ways of playing D&D range from treating it as a tactical war game to be won to using it as improv theatre and everything in between. All of these are valid and it's you job to give the players (including yourself) what they want out of the game.
Take 5 minutes next time you meet to find out what type of play each player prefers and describe your preferred style to them.
I think of agency as:
Players making informed decisions that have reasonable consequences
The D&D 5e Player's Handbook neatly encapsulates this in the "How to Play" section on page 6 and it is applicable to all RPGs that have DM/GM (some don't):
The DM describes the environment
The players describe what they want to do
The DM narrates the results of the adventurers’ actions
"I kinda got nerdy and got really into setting the scene. It was an opening narrative, so it took about 4–5 minutes for me to give all the backstory to the local area."
Cool, at what point did this lead to step 2: The players describe what they want to do? How much of it was describing the choices they could make? How much of the information was relevant to those choices? RPGs are a dialogue, not a monologue; unless the player's feel like they are involved in the storytelling then they might as well be at a book reading.
Back story is fine but if it was good it would be part of the story; the reason it is back story is that it is not enough fun to be the story. Back story may need to be there (or not) but it should emerge from the play; not be read at the players.
Scene setting is about providing just enough information that the player's can see the choices and have enough information to intelligently choose one; remembering that choosing to seek more information is always one of the choices.
For example:
It's a dark and stormy night when the captain puts you ashore in front of the imposing wall of the jungle. "This is where I left your friend; I'll be back at dawn five days hence. Don't be late!"
The beach stretches off in both directions, a narrow strip of sand bathed in moonlight. There are no obvious paths into the undergrowth. Sailors are carrying your possessions off the longboat and dropping them above the high water mark.
What do you do?
The scene is set and its now the player's turn.
Do they have enough information to make intelligent choices? No but you have handed them the initiative and they are now free to ask questions about what interests them. They might:
- Talk more to the captain
- Ask about their "friend"
- Ask what supplies they have
- Ask what the jungle/beach looks like
- Decide to troop straight off into the undergrowth (your job involves enabling idiots, too)
- Cast some long duration spells
- Cast Fly to take a look round
- Do something neither you nor I have thought of which is where the ultimate fun of DMing a RPG lies - dropping players into a situation and seeing what they do to it.
Now it is possible that some player's will not be comfortable with taking the initiative but the overwhelming likelihood is that within the group one or two will shoulder leadership roles. If so, they can start the ball rolling; I would suggest that you ask the other players "Are you happy with that?" to up their level of involvement.
In the unlikely event that no one seizes the opportunity, you can go on to enumerate what you think they can do. Some people like to pick from the menu rather than having to write it themselves first.
Outsource it to your Players
I find this happens in games where there is an unspoken agreement that the DM is going to in charge of (everything) about the world, and the players are going to be in charge of their characters, and that's it. That is, historically, the way games have worked. But it isn't the only way they can work.
You could for example, sit down with your players, and talk about what kind of game you'd like to play, what kind of challenges they'd like to face, and ask them how they'd like to balance those interests. You can bring up these issues, and ask them for solutions. If nothing else, it'll prepare their minds for there being times in game when they won't get to do their favorite thing.
Build the Game Together
There are tools for building a game. Depends on how deep you want to go. If you're comfortable taking a lot of input from players on how the world is going to be, you could use Sparks For Fate Core. It's built to use with the Fate RPG, but there is absolutely no reason, if you understand Fate as a game, that it can't be used to build worlds for other games. You don't even have to allow Aspects to mechanically influence the game, just use Sparks as a worldbuilding tool.
This will likely make your players more invested in the world, and so they'll be more interested in the roleplaying opportunities you present. The GM still has ultimate say over what happens in the game, but the players get to say what they're interested in. It might depend on your GM style, and whether you're comfortable adapting to player input into the setting. For me, it actually takes work off of me to not have to come up with things I think will be interesting to the players. I can simply riff off of the things they've already told me they're interested in.
Taking one step back from the setting/game design of Sparks, you may find The Same Page Tool useful. This is a series of questions that prompts the players and the GM to talk about their expectations. As mentioned before, a lot of things can be unspoken in games because of a misguided expectation of "building suspense" or "preserving mystery" for the players. I'm here to tell you that you can talk about the meta game, and still have the in-game moments be fun and surprising. Throw out the unspoken rule that the first rule of the game is we don't talk about the game.
Rolemaster Zodiac
Rolemaster is an old school game that had a section called Gamemaster Law, which is useful to anyone who plays RPGs, whether or not they play Rolemaster (I never have). Like the astrological Zodiac, it categorizes players into different types according to their proclivities while playing, so that you as the GM can better organize them and deal with their needs and potential problem areas.
Try to remember that humans don't always fall neatly into stereotypes, but the ability to say "Oh, Kyle is a Dragon, he's gonna wanna loot all the corpses, I should probably prepare for that" is often useful. Or, "Stan is a Hound, he's totally going to want to find out what the barmaid knows about the missing caravan, I should probably give her stuff to say"
Best Answer
The traditional answer to this is, "Write it down and pass a note." In the 21st century, I might change that to, "Send a text." Of course, nothing prevents your players from passing the note around amongst themselves, or reading it aloud. In some circumstances, "Take one player aside and talk to him or her."
However, I think you might be asking two or more related questions at once; even if not, it's worth thinking about the cases where this sort of explicit information relay is necessary or useful.
Friendly, cooperative characters, all in the same place, relaying fairly mundane information. (I think of this as a default case in dungeon-crawly games, but it need not be.)
In this case, is there anything to be gained by this added layer of "realism"?
Circumstances where communication is possible, but either difficult, error-prone or dangerous. For instance, if the characters are planning a sneak attack.
In this case, there is clearly something to be gained—a sense of tension, an additional degree of difficulty or challenge, etc. But the situation itself presents a solution: Simply point out that for every act of communication, you're going to roll perception checks as appropriate for the targets. Then, actually do it.
If they're still meta-gaming inappropriately, pass notes or send texts or make the perception checks for the implied communication that the players aren't role-playing.
Circumstances where communication is just impossible, due to separation.
If simply telling them not to meta-game is impossible, you might take one player (or the separated group) aside for a few minutes and handle them, then let them rejoin the main group.
I personally find this cumbersome, and probably your players will, too. It is possible that after a few instances, you can ease up and say, "Okay, let's assume I'm taking these two aside..." after you've gotten them in the right mindset with stricter methods.
Circumstances where players have legitimate cross-purposes.
This one can be tricky even for well-intentioned players. I occasionally have trouble with it myself, as a player rather than a GM. It is, in my opinion, something of a skill—it's mildly difficult to consistently act as though you do not know something for an extended period of time, but if these pieces of non-knowledge accumulate, it can be hard to keep track of it all.
(This is in contrast to the other situations, which seem to me to be much shorter-term. I find that much easier.)
After a few sessions with any given group of players, I like to think I have a sense for what their hot buttons and their potentially opposing agendas are. (After all, as the GM, I probably helped set them up!) And so I often use that insight to guess when a private note might be appropriate, and if it's necessary.
Ultimately, though, these are tools to regulate the information flow, and remind the players to take part in that regulation. These tools don't necessarily make the process less awkward if these techniques are used constantly.