What is the one subject people need to learn more about?

My answer on Quora.

As a teacher I think that their should be a compulsory course on logic and critical thinking.

Key areas to be addressed would be

1. The nature of logic fallacy
2. Sound arguments from premise
3. causation vs correlation
4. Inferring motive
5. How to read and interpret graphs(including trends)
6. The meaning of uncertainty and error
7. Science as an inductive pursuit
8. Necessary vs contingent conclusions
9. Understanding bias, assumptions and paradigm