When an amateur player becomes inconsistent with his backhand loop, he just starts pushing…
 
When an amateur player becomes inconsistent with his forehand smash, he just starts blocking…
 
When an amateur player can’t keep his best serve short, he stops serving it…
 
When an amateur player has a problem, he can’t fix it. 
 
When a professional player encounters an inconsistency in his game, he realizes the problem, and immediately fixes it.