Self-serving bias is a psychological tendency where individuals attribute their successes to their own abilities and efforts, while blaming external factors for their failures. For example, if a student like John aces a test, he might think it’s because he studied hard. However, if he fails, he may blame the test being unfair or too difficult. This bias helps protect self-esteem and maintain a positive self-image. It can be seen in various situations, such as in sports, where an athlete like Sarah might credit her training for a win but blame bad weather for a loss.