To make us realize we need one another. God's ultimate goal for all of us is to experience and demonstrate genuine love. Love is built on a recognition of mutual need and a joy in giving to that need. Greater love has no one than this, that someone lay down his life for his friends. To remind us that life is short.
Life is like a vapor that appears for a little time and then vanishes away.
Then there is eternity that is without end. The purpose of this brief life is to prepare for eternity. To discover what is important in life. During a time of disaster, we realize that relationships are more important than things - especially our relationship with God through belief in His Son. To remind us of the curse of sin.