Electron spin explanation. Pretty good. I wish he hadn’t bothered with the classical explanation at the start. Who cares? That world just doesn’t work that way at that scale.

To me one of the most mysterious facts in quantum mechanics is that electrons have memories of previous states while being infinitely small point particles. Where is this information stored? What exactly stores it? How is it retrieved and under what conditions?

These are questions to which we’ll probably never know the answers; the universe just is that way.