Al Stover

“Superman comics are a fable, not of strength, but of disintegration. They appeal to the preadolescent, (sic) mind not because they reiterate grandiose delusions, but because they reiterate a very deep cry for help.
Superman's two personalities can be integrated only in one thing: only in death. Only Kryptonite cuts through the disguises of both wimp and hero, and affects the man below the disguises.
And what is Kryptonite? Kryptonite is all that remains of his childhood home.
It is the remnants of that destroyed childhood home, and the fear of those remnants, which rule Superman's life. The possibility that the shards of that destroyed home might surface prevents him from being intimate- they prevent him from sharing the knowledge that the wimp and the hero are one. The fear of his childhood home prevents him from having pleasure.
He fears that to reveal his weakness, and confusion, is, perhaps indirectly, but certainly inevitably, to receive death from the person who received that information.
[...]
Far from being invulnerable, Superman is the most vulnerable of beings, because his childhood was destroyed. He can never reintegrate himself by returning to that home- it is gone. It is gone and he is living among aliens to whom he cannot even reveal his rightful name.”
― David Mamet