We make thousands of decisions every day. Do I cross the road now, or wait for the oncoming truck to pass? Should I eat fries or a salad for lunch? How much should I tip the cab driver? We usually make these decisions with almost no thought, using what psychologists call “heuristics” – rules of thumb that enable us to navigate our lives. Without these mental shortcuts, we would be paralyzed by the multitude of daily choices. But in certain circumstances, these shortcuts lead to predictable errors – predictable, that is, if we know what to watch out for. Did you know, for example, that we are naturally biased towards selling investments that are doing well for us, but holding on to those that are doing poorly? Or that we often select sub-optimal insurance payment plans, and routinely purchase insurance that we don’t even need? And why do so many of us fail to enroll in our employer’s corporate retirement plans, even when the employer offers to match our contributions?