For me it is the fact that our blood contains iron. I earlier used to believe the word stood for some 'organic element' since I couldn't accept we had metal flowing through our supposed carbon-based bodies, till I realized that is where the taste and smell of blood comes from.
I had a conversation with my neighbor along those lines. He reads his Bible everyday. I asked him if he knew that God were real, 100%, something/someone he could reach out and touch, if that would change how he lives his life.
I answered before he had a chance and said in no way would it change mine. I live my values. He said it wouldn't effect him either, and I believe, he is a genuinely great guy. But the fact that that would change soooo many people is either terrifying or makes me super grateful that they have their reasons to not indulge their worst instincts.
Both are unsettling, really.
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