In defense of bad groups, you should note that few groups start out with this awful set of attitudes and behaviors. They evolve into these patterns because they find that the time spent on group activities is not a rewarding and productive experience. You need to make sure that the group is rewarding and productive, both for yourself and for other members. A good group, on the other hand, is accepting and supportive. Members share an understanding of the goals of the group, and they are committed to them.
Members listen actively and carefully to one another.
Members assert their own ideas without attacking the ideas of others. Good ideas are rewarded. Members look forward to partiapating because their ideas are respected. Everybody pitches in, and everybody wins. Support the ideas of other people vocally.