The term "crazy" or "insane" is often used to describe behavior that is wildly irrational or unpredictable. In psychology, it refers to severe mental disorders that significantly impair a person's ability to think, feel, or interact with others. Conditions such as schizophrenia or bipolar disorder can lead to episodes where individuals may act in ways that seem illogical or erratic. In everyday language, "crazy" can also describe something that is extremely exciting or surprising, such as a roller coaster ride or a party. This informal use highlights the contrast between extreme emotions or experiences and the more clinical understanding of mental health issues.