The trading floor description strikes me as what I think of as the "cafe experience". In a busy cafe (e.g. the one next to the university, a few towns over), a

The trading floor description strikes me as what I think of as the "cafe experience". In a busy cafe (e.g. the one next to the university, a few towns over), all the conversations can "blend" into a wall of sound that lacks much in the way of consistently distinguishable components. As a result, my brain stops trying to pick out the pieces, and my concentration actually rises. It's still exhausting, though, over the long term. 2 - 3 hours, typically, and I am somewhat fried. But it's at a subconscious level, rather than e.g. the frustration of the cubemate who insists on making speakerphone phone calls, or the one who's personal volume is always set to "11".