A type of question to consider carefully is Why questions. Why questions are fantastic after a positive experience or the player having done something really well. But the minute you say: “Why did you throw your racket?” or “Why did you behave that way?” – especially teenage kids will deny it.
They will go: “I didn’t throw the racquet three times.” They’ll justify it. “Oh, well, he made a bad line call or annoyed me” or “Well, my favorite player throws his racquet, so why can’t I?”. So, it’s downward rabbit hole spiral. Just be mindful of it.