System 1 is our fast, automatic thinking which relies on mental shortcuts and biases. System 2 is our slow, effortful, logical thinking. Daniel Kahneman introduced the concept of cognitive biases that influence our judgments and decisions in irrational ways. Examples include anchoring bias where we rely too heavily on the first information we receive, availability bias where we judge likelihood based on what we can easily recall, and planning fallacy where we underestimate costs and overestimate benefits of projects. It is difficult but important to recognize our cognitive biases so we can avoid making mistakes in judgment and decision-making.