I recommend reading about the Stern Gerlach experiment. I think that nails down what makes spin counterintuitive, and is a really clear example of how the predi

I recommend reading about the Stern Gerlach experiment. I think that nails down what makes spin counterintuitive, and is a really clear example of how the predictions of quantum mechanics can't come from classical mechanics. The fundamental nature of it and the units can be reasoned out by looking at conservation of angular momentum.