"Most of us avoid conflict as much as we can. The problem in groups, as in life, is that conflict is inevitable. Each group has to define its goals, clarify how it will function, and determine the various roles that members will play. Group members should expect disagreements about the content of the group's goal and how to solve specific problems related to that goal. Task conflict is a necessary part of this process because, from divergent points of view, a more unified direction must be agreed upon if group members are to work together in a productive way."
"On a more psychological level, task conflict is necessary for the establishment of a safe environment. Although at first glance this may seem paradoxical, task conflict promotes the development of trust. We all know from our own experience that it is easier to develop trust in another person or in a group if we believe that we can disagree and we won't be abandoned or hurt because we have a different perspective. It is difficult to trust those who deny us the right to hold different views. To engage in a task conflict with others and to work it out is an exhilarating experience. It provides energy, a shared experience, and a sense of safety and authenticity and allows deeper trust levels and collaboration."
"From the task perspective, if people are not free to express their points of view, the group's product is likely to be inferior. If everyone just goes along with the first idea that's expressed, the outcome is unlikely to be of high quality. Task conflict is a normal, natural, and necessary part of group life. Keeping that in mind will make things much easier."
(Susan A. Wheelan in 'Creating Effective Teams: A guide for members and leaders,' 3e p. 34 Sage)