THE THREE RULES OF GROUPTHINK
1. ILLUSION
A group of people come to share a belief that is not based in reality: an illusion.
2. CONSENSUS
As the belief does not match external reality, the group of people resort to hanging onto the only thing they have, a consensus between them that the illusion is reality. From this point, the illusion's main justification becomes this "consensus".
3. INTOLERANCE
Any external person to the groupthink with a different view needs to be silenced because the "consensus" becomes the only defence of the illusion. Therefore the groupthink group resorts to censorship, intimidation, and "cancelling" all critical opinions.