The "Why" Part of the Brain

   In my world, creativity is directly related to my state of mind or mood.  Some days, I'm seemingly unable to engage the necessary faculties to produce innovative designs. I'm not sure why this is, but I recognise it and adapt. I shift gears and go into manufacture mode and pump out all the small jobs that don't need creative attention. Occasionally, a conversation or event can alter the current mood and allow me to dive headlong into an idea or design development. Why? 
   It's an ironic control issue. The more I try to drive my brain in a direction, it seemingly applies the break, slowing the process. If I leave it to drive itself, it sometimes drives erratically, forcing a countering action. Some days creativity seems to be in a glider plane on autopilot, starting from a lofty point, then gracefully meandering to the obvious destination. Why?
   Some nights I go to sleep with a problem I wish to solve. A very sound rest occurs and the problem pops into my head as if the hand of god placed it there. Other times, I dream of a problem as if it were a tin can that I kick around until it's unrecognisable. I assume that there's many factors related to sleep that contribute to those questions. But why?
  I guess there's no clear conclusions for these questions. The billions of neurons  fire like a lightning storm in my head can't construct the reasons, but if I can just help guide the outcome, I will deal with it.