In this chapter we have looked at the effect that group membership can have on our behaviour. It is easy to slip into supporting your group, and often this has positive effects, but not always. Supporting each other is what makes a community strong, and can make life simpler and better for the individual members. The problems arise for people who are either rejected by the group or not in the group. This can create conflict at an individual level and also at a group or even national level. The puzzle for us is to balance the benefits of group cohesion with the obvious downsides of ethnocentrism.