No matter where you go in the world, you'll always encounter familiar places (everywhere has bars for instance) but it is the small differences that stand out and you tend to remember.
The best and most immediate of course comes with Ireland's greatest tourist attraction - a pint of Guinness.
No matter where you go in England, New York, France or Australia, you're always going to get a terrible, rushed pint. I've often tried giving the bar man/women explicit instructions on how to pour a pint of Guinness and it all goes fine until the initial 'rest period' where you need to leave the Guinness to settle for just over a minute until you top it off.
When I worked behind the bar in Belfast, you'd serve another customer and then come back to the pint and top it up. Easy. However for some reason, when I tell the bar staff in England to leave it for a minute, they almost always just stand there staring at it. Even whilst other customers are waiting. And so you need to spend the whole minute making sure they don't come in to early.
It's really annoying, often if you look down to just check your phone, or focus on the barperson and not the pint some other helpful member of staff will come along and destroy the pint for you.
In Belfast, often you'll pay for it and then the barman will tell you to go and sit down and he or a glass collector brings the pint over to you. It's great.
Also, it's generally accepted that you can ask the glass collectors for table service. You don't get the formality of a bill (or even a tray sometimes), but if they say they will, you just give them your money and order and they bring you back the drinks and change. It's great for when things are starting to get busy in a place like McHughes. You should always tip a pound or two when this happens though, it would be really rude not too.
Another great thing about Belfast bars is 90% of the time you can hand over your phone and they will charge it up for you. I think if I asked at my local in England if they'd charge my phone for me they'd think I was a nutter.