Last weekend I was helping a friend to deal with his "broken" iPhone XR. It was stuck on the Apple logo. No mather what we do the phone was just black and the apple shows up.

Us JavaScript programmers like to use words like, "event-loop", "non-blocking", "callback", "asynchronous", "single-threaded" and "concurrency". We say things like "don't block the event loop", "make sure your code runs at 60 frames-per-second", "well of course, it won't work, that function is an asynchronous callback!".