Since the the 2020 pandemic, the interest in investing in both domestic and foreign stocks – as well as cryptocurrencies – has surged again. As retail investors, everyone knows we must be careful about our psychology, yet many behavioral economics books overwhelm readers by listing 30 or 40 different biases. This course cuts through that complexity by focusing on four core concepts that reveal the weak links in our decision-making: over-extrapolation, overconfidence, prospect theory, and social communication bias. Viewing bubbles and crashes through these four lenses, the course aims to serve as a guide for your healthier and more successful investing life going forward.