It reallllllllllllly depends. I think the findings of Milgram's experiments justified the emotional turmoil some of the participants suffered as the means. But then you get something like the atomic bombs which ended WWII. The ending of world war two was certainly great, but I can't find it in myself to say this justifies such mass slaughter. And when you're doing something awful and promising it will be justified by the end... I don't like that 
This is a tough topic, I hope more people start pitching in

This is a tough topic, I hope more people start pitching in
