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.
The thing is, it’s moving that fast because of the expansion of space. ≈30 billion light-years over ≈14 billion years equates to over twice the speed of light. Does that mean there’s no crazy relativistic time dilation, and time is moving normally for them in our frame of reference, since they aren’t physically moving, it’s space that’s expanding? That’s just as wild to my brain