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 costprofessional, 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 others needs and produce a result thats more than the sum of its parts. When you try to accomplish that, tensions can rise and peoples emotions towards each other can intensify.