What upset Stanley most about his trial the book Holes by Louis Sachar?

In "Holes" by Louis Sachar, Stanley Yelnats is most upset about his trial because he feels that he is unfairly judged for a crime he didn't commit. He is wrongly accused of stealing a pair of sneakers and faces a harsh punishment without any solid evidence against him. The lack of support from his family and the feeling of hopelessness contribute to his frustration and sense of injustice. This experience sets the stage for his journey at Camp Green Lake, where he learns to navigate the challenges of his situation.