One of the more inconvenient aspects of civilization is that it interferes with the instinct towards fight-or-flight. When one is, say, on a hell-flight from Indianapolis and the Boeing 707 is answering to the controls with all the aptness of a disgruntled cow, one's first tendency is to rush up and down the aisles à la Marge Simpson, screaming "Let me out! Let me out!"
But we hasten to add that where not forbidden by law, this sort of behavior is heavily constrained by social disapproval. Like it or not, one must remain seated and resign oneself to a fiery death or to having to change in Newark, whichever comes first.
It is at such a moment that one notices the Sublime rather forcefully. The adrenaline in one's system at such a moment, having no better outlet, dramatically enhances the aesthetic sensibilities, particularly where Nature is concerned. As one prepares to leave this world, surely it never looked lovelier. (And yes, the fifty-year-old school librarian in the next seat probably never looked lovelier, as well -- but what with social disapproval and so on, one had best observe the Sublime through the window.)
An obscure phenomenon, certainly. But it gave rise to an entire subgenre of literature. The Gothic novel is all about the power of stark terror to intensify one's appreciation of Nature. Heroines, constrained by social expectation and/or tight lacing, are unable to offer resistance or to take flight when confronted by banditti or cruel guardians. So they instead observe the wonders of the local scenery with admirable acuity. If the heroine of The Mysteries of Udolpho has chosen to horse-pistol her tormentors instead of meekly marvelling at the beauty surrounding her, chances are we would have a much shorter and much less edifying novel.