What about Team Fortress 2? Never before have I seen such glee on the faces of people doing so much killing (and dying). Who cares if you become one of the fallen? The very next moment, you'll be spinning up your minigun again and yelling "CRY COWARDS! BOO HOO HOO!"
And don't tell me that it's ultimately sad because no one can rest in peace or truly kill their enemy, because they live forever in a neverending cycle of violence, death and renewal. The ancient Vikings considered that to be Paradise.