Rahvin writes:
What we do matters because our actions affect other people, both our contemporaries and our descendants.
More, this is the only life we have - we don't get some magic reset button for a new life after death. We can't wait for heaven, because it will never come. The world is how we choose to make it, collectively, and whether we make it a paradise or a hell is up to all of us.
To make a movie reference: "God doesn't make the world this way. We do."
There's no metaphysical reason for anything...but people have value, and improving the lives of people is a worthy goal without the empty promise of heaven.
OK but from a Christian perspective I don't understand the goal to be heaven. I agree with your goal but I believe that your goal in life in some way is a foreshadowing of, and a part of, a renewal of this world as opposed to leaving this world behind for some spiritual existence elsewhere whatever that might mean.
He has told you, O man, what is good ; And what does the LORD require of you But to do justice, to love kindness, And to walk humbly with your God.
Micah 6:8