You will probably find the book "Snakes in Suits" enlightening:

http://www.amazon.com/Snakes-Suits-When-Psychopaths-Work/dp/...

You know those charmingly manipulative psychopathic serial killers? It turns out many people like that just aren't violent. Instead, they like money and power.

A person like this probably feels just fine about what they did. "Psychopaths are without conscience and incapable of empathy, guilt, or loyalty to anyone but themselves."