Defense mechanisms are psychological strategies that individuals unconsciously use to protect themselves from feelings of anxiety, distress, or threats to their self-esteem. These mechanisms operate at an unconscious level and can help individuals cope with difficult situations or emotions. Some common defense mechanisms include denial, repression, projection, rationalization, and displacement. These mechanisms can help individuals maintain their psychological well-being and protect them from overwhelming feelings, but they can also be maladaptive if used excessively or inappropriately. Understanding defense mechanisms can provide insight into an individual's behavior and help with therapeutic interventions in clinical settings.