The way that I picture it is like a tapestry that God is weaving. Every single human being's life is like a thread in that tapestry. We are each learning things NOW, but when the tapestry is completed, and we gaze upon the finished picture, we will ALL learn exactly what God wanted us to learn by living this life on earth. Every life lived will benefit from every OTHER life lived, in this way. Our lives, EACH of our lives are threads in that tapestry... Mine, yours, the baby that dies at birth, the slave, the free, the rich, the poor, the abused, the abuser, the starving, the handicapped, the whole, healthy, unhealthy, every single life... is precious. Every single life is going to be part of this eternal (I say eternal because perhaps it will be like a monument almost...) tapestry that God is weaving... that will forever memoralize our experiences here walking this life with the knowledge of good and evil. Do you know what I mean? This life isn't the real life. This life is just the doorway into eternity. The suffering that happens now is nothing compared to the glory that will be revealed. Easier said than done if you are currently greatly suffering... but this will come to pass. And the tapestry will be made up of all of our lives and in the center of this tapesty, is the cross. God's act of love.
This life is a gift. Because we are experiencing love along with non-love so that we can truly understand what LOVE is. If this life was all there is, then yes... this life would not make sense. But this life is just the doorway to eternity. This life is preparing for us our REAL life. How better to understand something, then to actually EXPERIENCE it... (love versus non-love.)
No matter how long someone spends here.. they will ultimately learn what God wants them to learn by the tapestry of every life lived. We learn individually, and then as a whole. Just like it is on earth... we learn lessons as individuals, and we learn lessons as a whole.
Well, that's just the way I see it.
This life makes absolute perfect sense when I see it this way.