Why is it so hard for people to understand how supply and demand works?

This is not a rhetorical question, I want to understand. I’ve been trying to understand why people don’t seem to understand this concept for a while and I understand it pretty well, but not to the point of being able to explain it to someone who doesn’t. Does anyone know of any resources or websites that explain it well? I think a lot of people just don’t understand that when you lower the price on something you’re going to lose a lot of customers and that lowering the price on something isn’t always a good thing, there are other factors to consider.