I think a lot of the social stuff sounds like putting something else ahead of the game. I realize its a social event, but at the same time there is a reason you chose to play an rpg verses watching a movie, eating, etc. Without going into all of the "theory" out there, you're stratching an itch by playing.
As far as writing, the 'tude style of writing. Show me the game is awesome instead of telling me.
"I was talking to so and so, and they gave me this sage advice on what to do. Aren't they awesome, and aren't I awesome for having talked to them? This game is so much better because of this association, please purchase!"
I also do which isn't much, but it's enough for me.
I reckon gun-lists (like sword-lists and spear-lists) are OK in the appropriate place. It's a matter of set and setting - are you playing a game where the primary audience is the weekend-militia crowd? Are you riffing on a genre where weapon-specs are a standard part of the prose style? If so, detailed gun-lists are all go. In a "rules-lite" or "cinematic" game it would seem a bit unnecessary (but maybe nice to a have as a potential add-on). If it's a vital part of a cinematic/rules-lite/"narrativist"/whatever game, it's probably in the way.
My pet hate is any situation where the system is opaque - i.e. you can't clearly see what you get out in exchange for what you put in. I'm forever getting shafted by White Wolf on this one, as their system looks transparent, but actually leads you up the garden path into generalising your skills when specialists are way better. It also won't let you use your Kewl Powerz(TM) unless you bought the right stat-skill combinations earlier in chargen. Grrrrr.
I'm no fan of gun lists generally, unless its a guns kinda game. If a game lends itself to a guns list (such as a military one like 'Aliens' for example) I'd feel short changed without a detailed guns list.
I remember the Dracula RPG from Leading Edge proclaiming it had source material to allow you to play the game in any age. What this really meant is they had a table of stats for guns through the ages. Epic fail.
What annoys me in games is when the writers havn't done any research at all because they assume no one will notice. I don't expect academic level detail for historical settings (although its nice if I get it) but they should at least scan over Wikipedia to get a few facts straight.
This happens most often with Americans writing games set in the UK, and boy is it obvious to us over here when it happens. (I might also suggest another pet peeve is when games set in the real world ignore anywhere but America). A friend of mine recently reviewed a Call of Cthulu adventure set in England that had Stonehenge a couple of miles outside London among other inconsistancies. When he pointed out this in his review the publisher replied that he thought the reviewer was niggling over trivialities.
I'd also offer another thing that annoys me, when games are written as rulebooks you have to read rather than a game that will inspire you to play them. for instance, I found old WoD an inspiring read, even if it was a little pretentiously written. However, new WoD (which I like as a game) reads as if the authors are saying 'this is a White Wolf game so its cooler than you. We don't need to inspire you, we just need to tell you the rules'. Even if it is a new rules mechanic rather than a cool setting, games should inspire you with adventure ideas just from reading them and make you want to dive in and play. Not every game will do that, but its the ones that don't bother to try that annoy me.
Its a matter of level of detail and how you use it.
A Para-Ordinance 14-45, an American Smith and Wesson 4586, and a Czech CZ-97 are functionally the same - full size .45caliber semiautomatic handguns. However, whether you /the PC insists on only buying American guns even if they're more expensive, or being willing to take anything with a trigger so long as it costs less than 300 dollars is a notable bit of characterization. Guns can tell you a lot about a person the same way clothes or a vehicle can. Reasons for not caring a gun can also be pertinent - perhaps you're an atheist who doesn't believe in an afterlife. No killing because this is the only shot at existence is different from choice of no guns because the penalty for armed robbery is twice that of simple theft.
Taking this a step farther, a legitimate complaint about many role playing games is that they don't tell you much about role playing. Some have life path charts, and many tell you that concept is the first step in creating a character. Yet they don't talk about choice of lifestyle, or signature behaviors. Most technology is just presented as tools and interchangeable - as soon as you have the ability to get a +1 sword, throw that non-bonus item out. Cars are just generic, or a few top end models - never mind that some characters might have preferences.