OK, so windows on OS X represent "documents"; windows on Microsoft Windows represent "applications". Both of these metaphors annoy me. I think of them as "those things I want to look at, that the computer is hiding from me."
My attention is a resource to be conserved, and each of these abstractions/metaphors are an extra step between me and whatever it is that I want to get to, and each of them causes a variety of failures between user intention and action. Maybe I need to add another layer of abstraction on top of them.... maybe a QuickSilver plugin for PersonalBrain... or vice versa....