The sukkah is a strange place. Do it by the book and you'll be sitting at your most elegant furniture with the finest linen tablecloth, your most expensive porcelain and silverware set before you, as though this were your palace where you will rule forever. Until you look up.
When you do look up, you'll see your roof is a precarious assemblage of disposable organic inedibles that provide little if any protection from the rain, easily blown away with the first strong wind.
And, by the book, you have to look up.
Tell me, of what does this remind you? In what other temporary structures do we live as though they were permanent?
I can think of two: Our bodies. And the biosphere of planet Earth.
Our bodies, because for the first 40 years of the journey called life, most of us will not even consider the specter of a final stop. It is simply too overwhelming for us to digest: There was a time when I did not exist, and there will be a time when this "I" into which I have invested so much will simply vanish. And so, rather than come to terms with our mortality, most of us sit through life as though the movie never ends.
So too the biosphere. Something about it—or about us—provides the impression that as there is today, so there will always be water to drink, oxygen to breathe, fish in the sea and elephants roaming the savanna; as a child relies upon its loving and forgiving parents, so we trust the earth will never cease to grant us its bounty or to accept the garbage we bury in its bowels. We nod to the data that screams otherwise, bow our heads to the experts—yet something of our human intuition will not let us to absorb the notion that this world that mothered us could somehow be vulnerable to our actions. So we continue living upon it as though it were an absolute, as though the very act of existence assumes that this shall always be.
Until we look up. And there will always be those events in life that force us to look up.
Once you look up and come to the realization that we are travelers on a finite road, that nothing shall ever return as it was, that there is not a single object onto which you can grasp and rely with utter confidence, for none of it will ever be truly real—once you know all this, how then should you live?
You might say, "If so, who needs this transient world, this dark pit of nothingness? Let me escape to a higher reality. Let me ignore as much as possible this mirage of life." As many enlightened people before you have said.
Yet the Torah asks otherwise. That even if you were the most enlightened being, you must live in this disposable flimsy hut as though it were our permanent home. You must embrace this fleeting moment, celebrate it and cherish it as though nothing else exists, knowing that everything was created for this moment alone, that its Creator eagerly awaits the act of beauty you might do here and now, within this body and upon this magnificent planet.
Know that this moment will never return, and treasure it as eternity.