Pessimism bias is a cognitive tendency where individuals expect negative outcomes more than positive ones. This bias can lead people to overestimate the likelihood of adverse events, affecting their decision-making and emotional well-being. For example, someone might believe they will fail an exam, even if they are well-prepared. This bias can influence various aspects of life, including relationships, work, and health. It may cause individuals to avoid taking risks or pursuing opportunities due to fear of failure. Understanding pessimism bias can help people recognize their thought patterns and work towards a more balanced perspective.