Your description regarding the feeling you had walking your dogs is very similar to something which happened to me once just as I was leaving work, as I was walking out of my office.
As I walked out the door, everything felt very crisp, my mind felt lighter, and it was as if my senses were working at 200%. At that time I believe I experienced that same "clarity regarding anything I examined in my mind" you described. I thought about several things and knew in that moment exactly what needed to be done in each of them, with what felt like more than absolute certainty. It only lasted a few minutes, and had left by the time I returned home.
It's never happened again. When I think back on that day, I can almost feel it, like I'm grasping at that sense of clarity, but it always remains out of reach.