Adding to what minal has written, it appears that the world is a big learning space. This learning is what we call rise of consciousness. Once we start questioning the world around us, the objective of our being and all the whys and hows that exist in our life, we start moving towards a higher level of consciousness or shall we say the next class? That is also the reason that its easier to corelate with some and not with others. Its when our consciousness levels somehow are in the same level or we are in a same class in this big school, it becomes easier to corelate and to understand each other then with the person not at that level.
I believe that each birth is going to the next class.... if you have cleared your exams! With an ultimate objective of going to a different dimension altogether.