Conflict of interests and assumption of altruism
This approach may explain a peculiarity of groups: in case of a conflict of interests, there is an unconscious belief that the person will fight for the group to her detriment. Of course, when we discuss of this in full consciousness, we realize that it is not necessarily the case.
This a an annoying consequence: when one is in a conflict of interests he cannot tell others: "Hey, I have a problem,I can't act in the group's interest". And yet, this could help in most cases to find a third way enabling to reconcile individual and collective interests ; but this would mean that we are not just altruistic, contrary to what we have proved unconsciously with our communication to join the group.
Thus, one of the problem making cohabitation harder for mankind is that when a conflict of interests occurs, it cannot be discussed. It stays unsaid and sometimes unconscious (for example utters of anger that we try to justify with objectives purposes when they are just resulting from other causes of which we are not fully conscious...). What is left unsaid makes it difficult to solve problems generated by the group. It seems to come exactly from what enables us to get together: our ability to share information freely to show our capacity to join a coalition !