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 love going to the county faire each year to see the single stroke motors of yester year. they got an entire section dedicated to classic and steam engines and my wife gets mad at me when i just sit there listening to the belts and solo pops.