When someone says in public that "they know everything," it is not necessarily indicative of a grandiose delusion in the clinical sense. Instead, it is more likely an expression of confidence, assertiveness, or perhaps even a touch of humor. People often use exaggerated statements or hyperbolic language in everyday conversation to make a point, create emphasis, or engage in banter.
In a social context, saying "I know everything" could be a way to convey that the person is knowledgeable or well-informed about a particular topic, or it could be a light-hearted way of expressing confidence in their abilities. It is essential to consider the context, tone, and body language when interpreting such statements, as they often carry more nuance than the words alone.
While genuine grandiose delusions are uncommon in everyday conversation, people may display behaviors that demonstrate a lack of humility or an inflated sense of self-importance. These traits can be seen in some individuals with narcissistic personality traits, who may frequently assert their superiority, dismiss others' opinions, or seek admiration. However, it is essential to distinguish between personality traits and actual psychiatric symptoms, as only the latter would indicate the presence of a grandiose delusion.
In summary, using phrases like "I know everything" in public is more likely a common expression of confidence or exaggeration rather than a manifestation of grandiose delusions. However, if someone consistently displays grandiose beliefs and other symptoms associated with mental health disorders, it may be worth considering a professional evaluation.