The first article I read today was Psychology: The Man Who Studies Everyday Evil
This article discussed mainly everyday people with evil sides to them.
For example, narcissists or "the incredibly selfish and vain, who may lash out to protect their own sense of self-worth." Two people, Paulhus and his grad student Kevin Williams suggest this trait is linked to Machiavellianism (the coolly manipulative) and psychopathy (insensitivity and immunity to other people's emotions). These two traits lead to the "Dark Triad" which is just a mess of nastiness.
Robson also talks about different factors that contribute to someone being "evil." One is the fact that is is shown in modern culture that people are attracted to the anti-heros in movies, tv shows, etc.