Whats the worst design flaw of the human body? The neck? Breathing/eating w/ same tube? Exposed genitals? Lack of weaponry/defense? Something else?

I still marvel we made it this far considering how truly fragile we are...

Whats the worst design flaw of the human body? The neck? Breathing/eating w/ same tube? Exposed genitals? Lack of weaponry/defense? Something else?
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