I found the same to be true when I was in Dublin a few years ago. A group of us went out to a decent pub. Another guy and I ended up talking to two sisters (and the one sister's boyfriend). Long story short, the four natives were drinking like fish and decided that we all needed to go down to a club they knew. It sucked. It was like the worst parts of the 80s had all joined together with bad techno.
The night ended up being entertaining because the guy I knew managed to make the blonde sister think that her boyfriend had the hots for the red-haired (younger) sister. When we left, I think that the three of them were either going to kill each other, or end up in bed together.