The tourist parts are more expensive, I'm from Dublin and I wouldn't drink in, say, Temple Bar. It's over priced and mostly hens, stags. It does have a good atmosphere, however most would drink somewhere else beforehand and go into Temple Bar for one drink and the atmosphere.
The City Centre has its run down parts, like most places, obviously at night time it looks worse compared to day time. It use to have so many great bars and restaurants and shops, lots closed due to high rents. I use to socialise top of Stephen's Green, that was a bit more expensive than north of the liffey, but so much choice, again lots closed down. You could do a pub crawl and with the amount of pubs you wouldn't get very far down Grafton street.
As someone mentioned above the ticket system on the bus, we're use to it, there's different machines, different tickets, passes, fares etc and when you are familiar with a system you tend to get it done as fast as possible, like the 1st time I used the tube or maybe it was the underground when visiting London , I seriously thought I was going to be trampled to death, I couldn't understand the ticket system, turnstiles that I got caught in, people pushing and shoving, doors closing on me, so many steps, but I was a visitor, no clue whatsoever so understandably I pissed people off and it all felt hectic to me.
It's like any Country, the main cities are always more expensive, busy, more worn and torn, you need to go outside the main Cities where you'll get great restaurants and pubs, not as expensive as the city centre. We are very dear for everything so you do need to shop around for places to go.