Joy, to a photographer (well, to at least some photographers;-) is waking up in the early morning on a weekend to find a freshly brewed pot of coffee in the kitchen (thanks to a wonderful spouse), and seeing a dense fog blanket the ground as far as the eye can see! "My wife knows me so well!" I think, as she places a coffee mug into my hand, helps put on a warm jacket, and pushes me out the door with my camera gear with the words, "Go enjoy the fog hun!" And enjoy I did.
Though the fog lasted maybe an hour ... while I was dancing with my camera and tripod in a nearby park, searching for compositions and just reveling in the magic of how mist - like broken windows! - both hides and reveals beauty, I lost all track of time.
I have always found fog as something of a paradox. Objectively speaking, it obscures reality; hides details and cloaks the identity of things. Yet, subjectively - or, spiritually speaking - it points to the essence of the world by briefly revealing the whole fabric of which the world is woven. I am always distinctly aware of when the "magic moment" is over (and it is time to pack up my gear), for it is precisely when the fog lifts and the world is again "revealed" as ordinary and real.
As (my favorite philosopher) Chuang-Tzu reminds us, while our momentary glimpse of wholeness vanishes along with the fog, we can always find our way back (by our soul's eye) by discarding ...
"...the distinctions and [taking] refuge in the common and ordinary things. The common and ordinary things serve certain functions and therefore retain the wholeness of nature. From this wholeness, one comprehends, and from comprehension, one to the Tao. There it stops. To stop without knowing how it stops -- this is Tao."