Answer:
   
   We don't know why G-d created man. When we think, we use this finite
   mind to turn over ideas and let them evolve over time. G-d's Mind is
   infinite; G-d doesn't experience time subjectvely, and therefore G-d's
   Ideas are incomparable to ours--not just an infinitely ornate version
   of ours, but something totally different. What we do know is that G-d
   is good, and it's the nature of goodness to want to bestow that good
   on someone. Given that G-d is the ultimate good, what G-d bestows upon
   us is the ability to experience G-dliness. As it says in Genesis, "let
   us create man in our image, like our form".
   
   Jewish literature often calls the soul a "spark of G-d", and notes
   that when G-d breathed a soul into Adam "one who breathes breathes
   from within himself". Man therefore is given the opportunity to be
   creative, just like G-d is. Which means that the world is an imperfect
   one, because otherwise there would be little for us to do. Also, it
   means that we were given free will. We aren't automata that always do
   the right thing. We make mistakes. So, we're here to be recepticles of
   G-d's goodness. Why G-d wants those recepticles is beyond us. So what
   are we supposed to be aiming for with our lives? Simple: To become
   better recepticles. This means learning what those mistakes are and
   working on avoiding them. We should strive to perfect ourselves. This
   includes being creative, and therefore improving the world around us.