[derefr]

To go further: I don't really see a point to any negotiation that isn't a positive-sum game. And not for ethical reasons! To me, it doesn't matter if I or someone else gets more of a pie, because it's still just one pie and talking won't make more of it, so any time spent negotiating has opportunity costs that lower the aggregate ROI of our combined pie-slices. Negotiation spends pie. If the goal is to get the most pie, why waste time negotiating that you could be spending making pie less scarce?