As a scientist, I can wear a lot of hats depending on how I want to sell the work I am doing. Like most labs, I can self identify with my study subjects, the phenomenon that we work on, the tools we use or how we approach our questions. That leaves me a pretty broad spectrum of conferences to go to, some of which I have been attending for years and others which I have only recently started to go to. I have my "must attend" list, but I try and mix it up with the other conferences I attend to both expand my exposure and to see what some of the other meetings are like.
One thing that is rapidly becoming a law for me is "Over 4 parallel sessions = far less time spent attending talks". It doesn't seem to matter what the conference is or how many people I know there, I just can't get excited about a meeting with a shit-ton of parallel sessions. Rather than seeing it as a smorgasbord of tasty science, it feels like a firehouse of information that I would rather not put my face in front of. Maybe I'm just getting lazy in my old age, but running through the maze of rooms to switch between several of the 15 parallel sessions during an afternoon just doesn't do it for me these days. And how do the organizers know to pick the two talks I really want to see and schedule them simultaneously?
I go to big meetings sometimes for a change and it's a good way to catch up with people I haven't seen in a while, but I find that I spend less time in the talks and more time chatting with people during the day. I'm not sure why that is, but big meetings get to be less about the presentations and more about socializing.