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.
It’s taking semantics from one frame of reference and trying to apply them in the frame of reference of an entirely different scale, realizing that it doesn’t work the same way, and then claiming that it is therefore “wrong”.