And how do you win?

It's like a damn game. Everyone seems to know the rules, but no-one told me. I am barely even sure I am playing, trying to keep up by copying what the rest of them do. No idea what happens if I get left behind, but from the way everyone avoids it I don't think I want to. It makes it pretty damn hard to get ahead though.

How do you play? What am I allowed to do? I want to join in, but no-one has the time to explain the game to me.