A wondering from sometime past:
I think perhaps the reason that Lucifer and his equally delusional host fell was a very particular form of jealousy.
I think that when the Father decided to make man, the angel of light got ticked off. Sure he pretended to disdain our bodies with all their incumbent demands and messiness. But in reality, He was jealous.
You see, we are the only creatures in all of the created order, seen and unseen, physical and spiritual, who co-create new spiritual beings with Him. With Him we work to populate eternity with new souls, souls who can also choose to love and serve Him.
Or not.
Despite his puffed up braggadocio, his claims at superiority, Lucifer was pissed.
So off to the garden he went, tempting fruit in hand, to prove that he still had some measure of control. And he's still hard at it, pulling us into his maelstrom of envy and fear and pride and anger. Trying to get us to stop the co-creation, or at the very least, to distort it into malignancy, and succeeding in many cases. Getting us to kill the newest souls before they leave the safety of their mothers' wombs.
How he must laugh, and brag, and ridicule us for our gullibility. In watching us swallow his lies like vitamins, how assured he must be of his superiority.