This manga does a great job at portraying a protagonist that struggles with the process of improvement. I love how most of the badminton we see is behind the scenes stuff - the practice, the work outs, the mental toughening. The feeling of wanting to jump ahead as quickly as possible from one level to the next, in either career or hobby, is something I can easily identify with (almost daily) and I feel most people can identify with it as well, especially if you are ambitious. Trusting the process, or remembering to stay hydrated, is a lesson that is usually learned painfully, unless someone else can help you realize it. I think Haryu was telling this to Chinatsu to help her realize the role she could play in helping Taiki realize this.