"I mourn the loss of thousands of precious lives, but I will not rejoice in the death of one, not even an enemy. Returning hate for hate multiplies hate, adding deeper darkness to a night already devoid of stars. Darkness cannot drive out darkness: only light can do that. Hate cannot drive out hate: only love can do that."
--Martin Luther King, Jr.
Celebrate thwarting evil. Celebrate saving lives. Celebrate protecting people.
Celebrate your victory, but don't celebrate your enemies' defeat.
It's a subtle difference, but it's important. I like it when I can tell the good guys from the bad.
If I can't do that, if the good guys and the bad guys are exactly the same... what makes you think there are any good guys?
I may be idealistic, but we should always strive for ideals. That's what they're for.