There are people who seem to go through life with relatively little of
the rubricizing tendancy. They are suspicious of all labels, of
categories, of sweeping statements.... [R]ubrics are essential to
mental life; their operation results enevitably in prejudgments....
The most important categories a man has are his own personal set of
values. He lives by and for his values. Seldom does he think about
them or weigh them; rather he feels, affirms, and defends them....
Fences are built primarily for the protection of what we cherish....
When a person is defending a categorical value of his own, he may do
so at the expense of other people's interests or safety.
-- Gordon W. Allport. The Nature of Prejudice