
The first reason is that you simply do not trust each other. In “The Five Dysfunctions of a Team”, Patrick Lencioni writes that the absence of trust is the biggest reason teams do not work well together.
This is because we are not often trained to be vulnerable and to trust the people we work with. We ascribe bad motives to what others do. We snap to judgment of others. You need to build trust to make good decisions.
The second reason is a fear of conflict. We were taught in kindergarten that everyone must get along. Even if that means holding back on contrary views. If we don’t trust each other, we cannot have a good debate about options to solving problems. This hurts the team because we do not bring our best ideas to the table.