You can encounter a pub in the States, if you’re lucky. For many years my local was the Pig’s Ear. Owned by a Brit, of course. Good brew, good people, my name on the wall in several locations for diverse feats of drinking prowess, a darts team, waitresses who flirt, the whole nine yards. Sadly no more, the Ear was a second home for more than a decade of my life. I miss it.
I had the same thing in the Flying Scot in Scarborough, Ontario, Canada for a number of years. Run by two expat Brits who made sure that the good solid group of regulars had enough beer, food, entertainment, and other diversions (darts, pool, trivia, Christmas, New Year’s, and Hallowe’en paries, golf days, group excursions to the horse races, etc.) that it was more like a social club than just a bar. And it was indeed a second home. A number of us, myself included, would occasionally get pieces of mail addressed to us, in care of the pub. Sadly, it’s been gone now for about ten years–the owners closed it and returned to be closer to family in the UK.
I can’t speak for Irish or UK Dopers’ definitions, but the Scot, as it was affectionally known, would seem to me to be a pub–someplace where yes, you can get a drink; but there is so much more than just drinking to the place.
Pretty much everything said about pubs in this thread also applies to Australian ones (there is no pub culture shock for Brits or Aussies in one another’s countries). The only difference is that Australian pubs tend not to be quite as cosy. They’re traditionally big, tiled, and noisy. However, most of the unwritten pub rules of the UK hold true here.
I pity people who don’t like pubs, because pubs do so much more than serve booze, and they truly are social/civic centres. If I’m in a strange town and need advice or directions, I’ll just go to the nearest pub and ask. You usually get much better advice than you would at the “visitor’s centre” run by the council. Needless to say, country pubs are the best for this sort of thing. A few times I’ve been in the pub and somebody’s come in and yelled, “Anybody want a day’s work?” Or a young couple from the city will come in and ask to use the phone because their car has broken down, and next thing half of the pub is outside fixing the car.
I like pubs.
All right, but explain the appallingly bad carpeting.
There is one here in Sacramento, BonnLair. We’ve been frequenting it recently, since a coworker turned me on to it. We haven’t been there often enough to have our own mugs hanging behind the bar, but **Rhiannon8404 **is working on it…
You volunteering to pay for a replacement, which will be covered with spillages & stains by the end of the night?
Okay, I need to know the unwritten rules. I don’t want to be pummeled for an innocent mistake. What’s the worst thing I’m likely to do unwittingly?
If there is (proper) football on the TV it is practically de rigeur for you to declaim in a loud colonial accent.
‘Gee, can’t we get some real sport? Soccer is a girl’s game where I come from.’
It’s expected so try not to disappoint. 
Well we manage to do with a bit less agressivly ugly…we save the apallingly bad for the beer.
Bonzer’s first link above really is excellent. I don’t think there’ll be a consensus on what’s the worst (or easiest) breach of etiquette, but take a look at the ‘pantomime ritual’ here for my nomination.