Kevin and Bruce and the other contributors to this thread have added some great ideas and information.
Conflict is normal.
It is part of the gradient of behaviors that occurs when people with different ideas, expectations, goals and values communicate or relate in some way. Accounting conflicts with sales, in most organizations because the themes of each are different. Healthy organizations and individuals have effective ways of gaining closure. They move away from the emotional underpinning of the conflict and toward a bit of objectivity and perspective. Being able to do that quickly and effectively regains their balance and energy reserves.