When two people cooperate, they move along a continuum to a spot that is not ideal for either but that is more beneficial for the overall result. The adjustment comes at a personal cost–professional, emotional, reputational or financial. The cost is by no means lessened by the possibility of sharing the benefits. To cooperate, people need to come together, understand each other’s needs and produce a result that’s more than the sum of its parts. When you try to accomplish that, tensions can rise and people’s emotions towards each other can intensify.