Hannah Arendt on Adolf Eichmann

The trouble with Eichmann was precisely that so many were like him, and that the many were neither perverted nor sadistic, that they were, and still are, terribly and terrifyingly normal.  From the viewpoint of our legal institutions and of our moral standards of judgment, this normality was much more terrifying than all the atrocities put together. 

~ Hannah Arendt, Eichmann in Jerusalem: A Report on the Banality of Evil (1963)