In this chapter, I review evidence that suggests that people are particularly gullible to their own arguments and beliefs. People often hold their opinions with too much confidence, endorse wrong answers with almost as much fervor as right ones and assume beliefs without feedback are true. They often discount or dismiss the opinions of others too much, and give credence to a belief it is attributed to themselves. People also often suffer a paradox of advice: They do not necessarily know when they need to seek it, who to approach for it, or when the advice they are given is any good. To remedy some of these issues, people have to become more expert at weighing the credibility of internal beliefs and outside information (i.e., the weight they should give to it) rather than merely relying on its strength (i.e., the force of the message itself).