Personality traits play a crucial role in the UPSC Civil Services interview as they reflect a candidate's suitability for an administrative role. Evaluators look for traits such as leadership, resilience, and adaptability, which are essential for public service. Candidates with strong interpersonal skills and emotional intelligence can engage the panel effectively, showcasing their ability to work in diverse situations. Further, traits like integrity, empathy, and the ability to make decisions under pressure are critical for civil servants, making them key factors during the interview assessment.