In Haikyuu!!, flashbacks are used strategically to provide viewers with insights into the characters' past experiences, motivations, and relationships. These flashbacks often showcase key moments from the characters' past that have shaped who they are in the present. By delving into their backgrounds through flashbacks, the show helps viewers better understand the characters' personalities, goals, and development throughout the series. Additionally, these flashbacks also create emotional connections between the audience and the characters, making their journey more compelling and relatable.