Letting a group take what appears to be its natural course without trying to steer it or to create leadership, structure or method is inviting disaster. Two writers on group theory put it bluntly. You are not born with group skills, nor do they magically appear when you need them. The way to learn them, obviously, is by working in groups. But during that work, you will have to force yourself and, on some occasions, force the group into seemingly artificial behaviors.
Group work is no different.