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 world would be better if we just used UTC everywhere.
or Decimal Internet Time, which is way easier to do calculations with, easier to distinguish from local times, and is less eurocentric