This is an explainer video on group-think. Group-think is the practice of thinking or making decisions as a group in a way that discourages creativity or individual responsibility. Tendency of the members of a group to yield to the desire for consensus or unanimity at the cost of considering alternative courses of action. Group-think is said to be the reason why intelligent and knowledgeable people make disastrous decisions. In the video it showed that Dave wanted to sell used tissues. Group-think was explained nicely in the video. Also about the kinds of people that think differently about the opinion of others that affects group-thinking. Sometimes, showed in the video, group-thinking can lead to dangerous results and there are 8 symptoms. Those symptoms are an illusion of invulnerability, collective rationalization, belief in inherent morality, stereotyped views of out-groups, direct pressure on dissenters, self-censorship, Illusion of unanimity, and lastly “Mind guards” are appointed.