Emotions are complex mental reactions that involve experiential, behavioral, and physiological elements. They are subjective states of being that involve physiological arousal, psychological appraisal, and cognitive processes. Emotions are how individuals deal with matters or situations they find personally significant. Emotional experiences have three components: subjective experience, physiological response, and behavioral response. Emotions are often confused with feelings and moods, but the three terms are not interchangeable. Feelings are conscious mental experiences that arise from emotions, while moods are longer-lasting emotional states that are less intense than emotions.

Emotions can be categorized into basic or primary emotions, such as happiness, sadness, anger, fear, surprise, and disgust. These emotions are considered universal and are experienced by people across cultures. There are also secondary emotions, which are blends of primary emotions, such as remorse, guilt, and shame.

Defining emotions is a task that is not yet complete, and many researchers are still proposing theories about what makes up our emotions. However, there is a good basis of knowledge to analyze when exploring the topic. Theories of emotion suggest that our emotional states are combinations of physiological arousal, psychological appraisal, and subjective experiences. These appraisals are informed by our experiences, backgrounds, and cultures, so different people may have different emotional experiences even in response to the same stimuli.