|From Married to the Sea|
Call it what you want. God. Self. Superego. Society. I can't seem to not play it.
Regardless of the source, why would we engage in such self-hatred, self-loathing, self-destruction? If depression actually can play a positive role in the evolutionary process and survival, might "hitting" yourself also play such a role. It's clearly a human response and almost seems to be involved in whatever it is that allows us to create society.
And from a spiritual viewpoint, maybe that's what the above picture really depicts. Maybe when Jacob wrestled with the angel, he was engaged in this self-hatred or self-correction.