groupthink refers to the tendency for all members to think alike and suppress disagreement for the sake of harmony in a group. This conformity may cause negative situations such as self-censorship which makes the dissenters in the group to keep quiet and hence there is pressure on them to conform.
On the other hand, there is "The Wisdom of Crowds", which means that the crowd's judgment is often more accurate than that of its individual members. By concerning the whole group, Diffusion of responsibility which refers to the tendency of members to avoid taking actions as they assume others will, bystander apathy, and deindividuation referring to the loss of awareness of one's own individuality, may be resulted in.
When I was F.5 I was a house captain of South House of my school. I had a group of committees and friends to work for the house fighting for the champion of that year. There were 4 houses and we all thought that our own house was the best and the others were losers. We even saw one another as enemies and sometimes there were conflicts about the attitude towards each other. We might stereotype the students into their houses and hence determine their impression and how to treat them. For example, West House was closer to my House and North House was the one we disliked most. When we saw a West House member we might think that he was a friend. But when we saw a North House member, we might think that he was not good and hence the attitude towards him was worse, even we did not know both of them.
I have a group of best friends of 13 people including boys and girls since junior secondary school. Now, we are separated and go to different tertiary schools but we...