I don't know if there is an afterlife, or a supreme being. I'm very much a "see it with my own eyes" kind of person.
I honestly can't imagine a deity with less compassion than I myself have so I don't worry about it much. I figure that the afterlife will either be an improvement or not exist at all. I black out with sleep almost every night so I'm quite familiar with oblivion, it doesn't scare me.
All the same though, I would like to live as many days on this beautiful, fucked up little planet as I can. There is a balance, as much as I hate to admit to such a cliche. Every day humanity displays its worst. And its best. World peace is NOT happening in our lifetime so just let go of that unobtainable standard right now. What IS possible is better. We can make the world a better place. If there is an afterlife, yay, we've scored points. If there isn't one, we've made a difference where it actually counted. Win/Win.