What's your definition of brat?
Aren't you a fan of Goran Ivanisevic? He did those things you've just mentioned all the time.
Haas is acting like he is some robotic programized Goat, not like a guy who is enjoying in last few months of professional tennis. Opponent hits a winner and he starts to talk with everybody, hitting the balls, unsatisfied with everything like he missed the easiest balls. Then if opponent hits the line the same story etc... The best example was Dupuis match a long ago in Wimby . And he is more or less like that all the time