"So if you want to be out there helping to change the world in useful ways, it's really really helpful to have some understanding of models."
— Scott E. Page
This is one of several arguments that Scott E. Page makes in motivating his free on-line video course Model Thinking. Essentially, Page argues that models help us to understand, predict, and design or re-design our world. This is going to be an important class. I am getting ready for a deep dive!
I have only dived deeply into two other free on-line courses. They are Linear Algebra and Introduction to Databases. I love learning about big picture, broadly useful subjects.