Do you mean why do we focus part of our awareness in this level of consciousness we call the physical?

  Lot's of different answers for different folks i imagine, and also a fairly universal one of growing in the PUL kind of love and waking up to our full conscious awareness of Oneness (not something we magically get when we go into the "afterlife" or other dimensions/focuses/levels or whatever you want to call it, slices of pie work fine too). 

  But originally?  Probably goes back to the beginning of individuated consciousness.  Some parts splintered themselves off from the Whole and sort of got lost and stuck.  My sense is that physical earth when thought up was originally a much more harmonious pattern that was more fluidic and thought influenced, more like the "afterlife" that we can shift our awareness to now. 

  For whatever reason, a percentage of those lost and splintered selves found themselves focusing here, and sort of started messing with the harmony and the pattern, and as they did so, it crystallized more and more, become more set and structured, less fluidic, etc.  In a sense, the physical became an externalization of inner "stuckness", but mixed with the pattern of something originally in balance and beautiful.  The beauty here in Earth is real, but the form and the over attachment to same is the illusion. 

   Then some of us decided to help out the ones who got stuck, and what happened.  Well, truth can be found in strange places at times, "The Sons of Elohim looked upon the Daughters of men and found them fair."  A good number of the helpers who came, also got stuck to some degree.

   When we hurt or contribute to the limiting of others, we create "karma" for ourselves.  That's just a fancy way of saying the inner core of us always seeks to right wrongs and seeks balance and Wholeness, and one of the ways we do same is by experiencing what we have contributed to others and the Whole in general.  In an overriding reality of interconnectedness, it's hard not to be a sharer on some level, and the more you wake up, the more you realize how much you want or rather need to experience and rebalance those errors in relation to others. 

   Course, some got attracted here just because of curiosity, it was a different pattern than many other patterns we had become aware of.  More chaotic, more loud, more exciting.  Imagine listening to the more boring forms of classical music all your life and then suddenly hearing some crazy, slightly discordant improvisational jazz in the background. Yet, it's hard to not become part of such a pattern if you focus too much on it.  It's easy when focusing here to likewise become stuck and imbalanced.  There is a collective, built up pull, a gravity of sorts.  That's why there is another saying from that strange book which again has some truth, that "Satan is the prince of this world".  Symbolically speaking that is, meaning welcome to the area of consciousness of crystallized, concentrated rebellion to the Creative Forces and Consciousness.  The land of imbalance and unlove. 

  If you partook, well you got to dig yourself out.  It's the place we need to heal, for its the area of consciousness that is actually within us, the collective woundedness and imbalance.  It's the externalization of that consciousness within, of separation, of error, of imbalance. 

  The good news, we are in the process of healing it, of "retrieving" it and eventually many of us will become fully free.  Free to be the full Co-Creators with the Creative Source Consciousness that we were meant and hoped to be.  Still needs a lot of work and helpful focus though.  Every little bit of positive energy, of opening to love, helps.  Some are here more for themselves and their individual growth processes, i.e. working out karma, specific areas of emotional and spiritual growth, and some here are more here for others, many of them the original helpers/retrievers who came in way back when.  There were 'retrievers' created in the beginning.  Bruce saw true enough on that. 

  And there is probably more to it than i'm aware of also. In not having perfect attunement or balance, how can one be perfectly aware and cognizant?  Not possible, only temporarily when temporarily lifted up by another or collective who is. 

In trying to explain what you feel it seems to become more difficult because the words get in the way. We are multidimensional, absolutely sure of that. Our dreams are insanely creative! I sometimes pray to become more lucid in them, so as to be more conscious in them.

I AM. Could it be not so much about responsibility, but more about letting go, becoming more open, spacious like the sky. This allows the greater love that we are to show itself to us. It becomes apparent in unexpected moments...perhaps in nature, in meditation, in heightened states of relationship with others, at the time of our deaths?

This dimension of yourself can recognize itself. The greater Other of Yourself can speak to itself as Lucy. Or seagull. You might be walking on a beach and the rocks speak to you as you pass by. Or something that seems impossible actually happens to you. Or maybe you are on the edge of sleep and something speaks your name without words. This is how it might happen.