I don't know why sometimes people complain about him serving under arm. It is not forbidden by the rules so why the hell he wouldn't use it? I heard comments that it is disrespectful. Why would that shot be disrespectful and short ball wouldn't (or lob shot in football)? It is just another way to try to gain advantage.
Saw this moment, bu this is not again any rule. However he complain whole match to referee on Nadal time. So far Kyrgios or any other player should learn that Nadal have ritual for every point.
He always have 3 bottle of water or something else, always takes 2 towels to both sides, he always have some strange ritual with serves, but shoulders nose ears.
Whether what type of ways to make them relax before the game commences, most important is they should maintain focus and strength while in the game. I can see Nadal that he's having that advantages with other players, that's why the upbringing was positive and he would 100% won the match. If every tennis player like Nadal could manage more than that, I guess many Nadal like who could beat him for good rounds.