The "Hedonic Treadmill" is a psychological concept that explains how people quickly return to a stable level of happiness after experiencing positive or negative events. When individuals achieve a goal or acquire something new, such as a new car or a promotion, they often feel a temporary boost in happiness. However, over time, they adapt to this change, and their happiness levels revert to their baseline. This phenomenon suggests that external circumstances, like wealth or success, have a limited long-term impact on overall happiness. Instead, people may find themselves continually seeking new experiences or possessions to maintain their happiness, leading to a cycle of desire and adaptation.