Mass Hysteria

http://www.steinski.com/blog/a-few-examples-of-mass-hysteria-in-us-history/

Lynching 1860-1960

In the south, if a black man was accused of so little as looking at a white woman, he was at risk of being taken from his home, mutilated by a mob, lynched, and burnt. People were proud to live in areas where black people were at risk of being lynched.
Definition: "an uncontrollable outburst of emotion or fear, often characterized by irrationality, laughter, weeping, etc." (reference.com)