[Really!]

I'm certain the deaths of Hitler, Mussolini, Stalin, Sadam Hussein & Osama bin Lin made thousands, if not millions, of people happy ...
They probably day dreamed about it, too!
The threst of a hostile take over/war is one of the greatest challenges that absolutely does motivate people to stand up & fight for their country, loved ones, freedom as well as their religion ...
When surrounded by dead comrades, soldiers are also motivated by their loss, but mostly, their conditioning to hate their enemy ...
The strength to continue fighting/killing comes from the depth of one's soul as well as firmly held beliefs in knowing they are doing good for the suffering ...
Some people are born to be soldiers & military leaders ...
The psychopaths mentioned above, I believe have had their energy broken up or obliterated to not ever be incarnated again ...
At the same time, I believe more will be born ...
It matters not to me if there is an underworld ...
Just the implication that hell exists makes it so much easier to find some semblance of peace ...

Spiritual growth is also spurred by some of darkest events a person can/will experience ...