Fantasies, often referred to as dreams, are mental images or scenarios that occur during sleep. They can be vivid and emotional, reflecting our desires, fears, or experiences. Dreams typically happen during the REM sleep stage, where brain activity is high, and they can vary in content from mundane daily events to fantastical adventures. These dreams can serve various purposes, such as problem-solving or emotional processing. Some researchers believe that they help us cope with stress or rehearse social situations. While the exact function of dreams remains a topic of study, they are a universal aspect of the human experience.