The event loop one was a must-watch video for anyone who write Javascript. It even secured me a job offer.
The fact I didn't know about these concepts is the reason why I always struggled to understand examples involving setTimeout, setInterval, etc.
Most videos on YouTube, even from well-known personalities in the programming YouTube community, simply jump into things without context at all even when the videos are titled "for beginners". Even some books and docs simply describe the spec without providing context and motivation.
Edit... Forgot to say Philip does an outstanding job in that video. He's even humble enough to admit it took him a few months to grasp what was going on.