Invulnerability is a wonderful asset to possess, but once lost is impossible to retrieve. The air above all ills is remarkably thin, making the taking of simple breathes a struggle for those not ideally suited to its rarefied condition. The accent to imperviousness is a matter of survival, overcoming each and every small physical and psychological barrier as they arise, continuance works adequately, moving ever forward unphased or unhindered by the roadblocks. Adulthood itself is a triumph, just overcoming the multitudinous threatening peaks that bar entry to the nirvana of accomplishment a miracle.
The road up is long, hard, tedious, adversarial, but mother nature being a reasonably honest foe, once gained extraordinarily comfortable, easily retainable, pleasantly, and constantly rewarding.
Unfortunately the route down is an extremely efficient escalator, and once stepped upon impossible to dismount. Descent in unnecessarily easy, and disturbingly final.