I believe to to be an NBA referee you have to be able to instruct others in a calm way. When you are in front of thousands of fans and you have to tell the team, the player and their fans what they have done was "wrong" or something of that nature, you have to try and not be to rude about it because chances are you will already be getting a mouth full from everyone, so adding bad behavior onto that will only make things end badly. You should have some history in the sport. It would not make sense to ref a game that you have not been had a personal experience with. Whether that was playing basketball growing up, or becoming a referee at the high school or college level. This job also requires a lot of integrity. You have to be completely honest all the time whether you are not a fan of someone or if someone if being rude. You can not allow people to call your shots. To become an NBA referee you have to go to a training camp. They have to watch many tapes. and take many quizzes. They also have to spend many hours studying the rules and regulations of basketball and watch how other referees come up with their techniques on how to do things. Dick Bavetta was the oldest referee the NBA had. Since 1975 he never missed a game where he had to ref. He even has the record for the most games officiated.