"Company, villainous company, hath been the spoil of me."— Shakespeare, Henry IV Part 1, Act III, Scene III
"When great changes occur in history, when great principles are involved, as a rule the majority are wrong. The minority are right."— Eugene Victor Debs, U.S. labor leader and pacifist (1855–1926)
The most famous example of Groupthink: the advisory group that almost led John F. Kennedy into invading Cuba and potential nuclear war in the Bay of Pigs tragedy.