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 fuel injectors are off when engine braking. It is the momentum of the car that keeps the engine running/rotating. That is why you are slowing down more rapidly because you’re losing momentum into the engine.