The appeal to personal interest, or the argumentum ad personam, is the logical fallacy of appealing to the personal likes and interests (preferences, prejudices, predispositions, fears, etc.) of others in order to have an argument accepted, when those personal likes and interests are irrelevant to the truth or falsity of the argument.[1][2] The fallacy is thus one of relevance.
A common example is prefacing an assertion with "As all intelligent people know," which plays upon the listener's desire to be seen as intelligent or fear of being seen as unintelligent. The argument is fallacious because the preface has nothing to do with the truth or falsity of the assertion that all intelligent people allegedly know; one could use that preface with any assertion, no matter how clearly wrong. Such an argument is also known as the "Emperor's New Clothes" argument, after the story by Hans Christian Andersen. In this example, the appeal to personal interest overlaps with the no true Scotsman fallacy, since the person using the fallacy can instantly dismiss any disagreement as coming from unintelligent people.