The average human being is actually quite bad at predicting what he or she should do in order to be happier, and this inability to predict keeps people from, well, being happier. In fact, psychologist Daniel Gilbert has made a career out of demonstrating that human beings are downright awful at predicting their own likes and dislikes. For example, most research subjects strongly believe that another $30,000 a year in income would make them much happier. And they feel equally strongly that adding a 30-minute walk to their daily routine would be of trivial import. And yet Dr. Gilbert’s research suggests that the added income is far less likely to produce an increase in happiness than the addition of a regular walk.