The Goy Effect is when a person(s) blindly tells you something about yourself that is not true. They use this as a winning argument to discredit what you had previously said.
John: Did you know that Jews are actually Satanists?
Jim: That wouldn't make since, Satanists do not push beliefs/proselytize. It is against our nature.
John: Come on, of course you push your beliefs. Nobody in their right mind would follow the Devil.
Jim: Obviously you are just stupid. Do your research next time.
Jim Later: *thinking* The Goy Effect really brings out the worst in people. Maybe they should do their research next time..