There is a well-known Jewish tradition that on Yom Kippur we strive to emulate the angels: We abstain from physical pleasures (food, drink, washing, leather shoes, marital intimacy), we wear simple white clothes, and we stand for long periods of silent prayer. In this, we demonstrate our desire to free ourselves from domination by our physical needs, to be, like the angels, humbly obedient to God and innocent of sin.
This imagery is very beautiful. There's only one problem.
It doesn't work.
However I try, after spending 25 hours without eating, drinking or washing, much of it standing in uncomfortable shoes, I don't feel like an angel. I feel hungry, thirsty, dirty, weak and achy.
I can ignore those feelings to an extent, but they won't go away. Persistent angel-emulation would quickly leave me bedridden, ill, and, before long, dead.
In case you hadn't realized, there's a tiny but crucial difference between me and an angel. Angels, I understand, have no physical bodies and thus no need or desire for physical pleasures. I do, and I'd like to keep it that way.
The more I try to behave as if I don't, the more I succeed in proving the opposite.
I suspect that's the real point of the angel-emulating metaphor. Our day of ersatz angelhood only serves to demonstrate how unlike angels we really are. We are physical beings, with all their intrinsic vulnerabilities and weaknesses. We cannot change that, however much we might wish to.
Were God to have wanted unquestioning, unerring, obedient servants, he would have created us as angels, not as weak and fallible men. As men, though we can strive to perfect our behavior, we will inevitably fall short - often far short - of God's demands.
On Yom Kippur, we implicitly beseech God to judge us as the men we are, not as the angels we cannot be.