Humanity's greatest flaw is its penchant for self-delusion; the ability of humans to convince themselves of anything, regardless of reality, and its resistance to change opinions when presented with evidence due to confirmation bias.
Madness string 9109
There's no such thing as a stranger; we're all equally backwards and wrong. Sharpened axes, not wits. Bones are broken by sticks and you never be free till you're strong.