Acharya Prashant addresses the issue of overthinking and anxiety by explaining that the mind naturally tends to dwell on trivial matters when it lacks a sense of purpose or importance. He compares random, unimportant thoughts to pathogens that are always present in the environment; one cannot eliminate them entirely but can develop 'inner immunity' by focusing on what is truly worthy. When a person does not have something significant to occupy their mind, a vacuum is created, which the mind then fills with useless distractions and everyday trivia.