Y Combinator's (YC) approach to selecting startups focuses on identifying ambitious ideas and determined founders rather than following industry trends. Despite minimal changes to its application process since 2005, YC's data offers insights into startup successes and failures, with determination being a key factor in a founder's success. The network effect within YC, driven by alumni involvement in the application review process, fosters a supportive community that benefits both individual startups and the incubator itself. YC values long-term, ambitious projects over trendy or incremental ideas, emphasizing the importance of resilience and innovation in its selection criteria.