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 combustion engine. I know technically it’s not but ultimately we as humans found a way to harness the power of explosions and make them do our bidding. honestly, one of humanity’s finer achievements. yes, it’s not without its barbs like emissions, but that’s a small price to pay for the workload any vehicle can provide.