Picking a hostel is hard work. I've realized that from now on I just need to not read everything so intensively and instead just read about a few and pick, because it is not worth the extra time and worry when so much is left up to chance of things that aren't really reviewed and the atmosphere when you are there.
My first hostel, Kinlay House, was for the most part meh. But I figured out from talking to other people I met there and some in Belfast that a lot of the hostels in Dublin had the same issues so I didn't worry about my inferior decision making too much.
First of all, this hostel was very big. You might think this would be conductive to meeting people, but alas it is not. I'd compare it to going to a big university versus a small one, at a big one there are more people but its way easier to meet them at a small one. I don't know if this is all big hostels or just the timing or whatnot, but a lot of people seemed to be staying for a long time or in bigger groups there for studying, so it felt more like a boarding house.
In addition the hostel website and reviews were misleading on a few things. The 'hostel bar' was actually a regular bar with a common back alley which is really not the same because it's not a common meeting place. The walking tours and pub crawl weren't actually run by the hostel either, they just would direct you where to go. Also the common room was like up a weird hallway and stairs which I didn't even see until it was my last day there, and the other common area was mostly focused on eating and people doing work or whatever.
There was one really nice staff member, a guy with tattooed arms who was semi-cute, but the rest were pretty formal and not that helpful. Facility wise it was fine, the bed was hard but not too uncomfortable, the bathrooms were clean and the kitchen was easy to navigate.
I ended up talking to one girl from my room a fair amount, I went out with her and some people she knew to a German DJ who was insane (well the dj wasn't really insane, just all the people there.) I was with four or five other people from all over (Netherlands, Germany, etc) and we all were weirded out by how crazy the people at the club were.
Overall it was a good learning experience and I know more about what to look for in hostels now as well as times to avoid. My second one and the one I'm at now were much easier for making friends.