Every interaction a company has with its suppliers can set off an endless series of tactics and countertactics. It's like a wrestling match. Both sides invest so much time and effort in trying to anticipate the next steps by the other that the focus is turned away from the best interests of their organizations. This comes especially true during the negotiation phase of the procurement process.
Negotiations between buyers and suppliers have traditionally assumed a zero-sum outcome: Each party does not benefit except at the expense of the other. The end result of this tactic/countertactics spiral is a combination of inefficient decision-making, obscured visibility, and contentious working relationships.