The traffic manager analogy for the Event Loop is a good one. I usually explain it to new engineers as a restaurant kitchen with one chef: the chef does not stand at the oven watching a dish cook — they hand it off, move to the next order, and come back when it is ready. The moment the chef starts watching the oven is when the whole kitchen backs up. Same thing happens when you block the Event Loop. Nice post, solid foundation for anyone learning Node internals.