in management, is conflict good or bad

In management, conflict refers to the long-term management of intractable conflicts. It is the label for the variety of ways by which people handle grievances -- standing up for what they consider to be right and against what they consider to be wrong. Those ways include such diverse phenomena as gossip, ridicule, lynching, terrorism, warfare, feuding, genocide, law, mediation, and avoidance. Which forms of conflict management will be used in any given situation can be somewhat predicted and explained by the social structure -- or social geometry -- of the case.
It is not the same as "conflict resolution." The latter -- conflict resolution -- refers to resolving the dispute to the approval of one or both parties, whereas the former -- conflict management -- concerns an ongoing process that may never have a resolution. For example, gossip and feuds are very common methods of conflict management, but neither entails resolution.