Not to be flippant with people's serious relevant work and observations, but I believe it's time for a joke I heard (on a compositor's forum) that seems to provide levity and illumination on this thread:

Of course, Relaxing back and looking at white, puffy clouds slowly moving across the blue, blue sky is conducive to daydreams, reflections and thoughts.  What goes through the mind of a compositor, on such occasions?
That's easy; they're thinking:  "Man, does that look fake!".