Behaviour is an interesting thing. On the spiritual side of all budo and all things you will find it is a must, a discipline of the utmost importance.
Speaking of Richard Kim, he quotes his teacher, Yoshida Kotaro, as saying there is a difference between attitude and behavior in that we can fake an attitude, but we can't fake our behavior. Our fake attitude may impress people, but eventually, our true nature is seen in our behavior. Further, he says, we're always the last to see our own behavior.
Anyway, I say, it's better to be yourself and behave as you will, intentionally, instead of not being your true self and therefore behaving unconsciously.
My first karate teacher, in 1972, had a picture of himself in a group with Mas Oyama, the bull killer. He had a wall hanging that said "Kyokushinkaikan Karate Do" and claimed some degree of black belt with Oyama.
Later, it turned out the picture was from a seminar this guy attended with Mas Oyama in Alabama, but the guy who organized the seminar, an actual black belt under Oyama, said that the fellow in question was only a green belt. He had black belts in other types of karate, apparently, but he claimed the one art he didn't have rank in. I left his class to train with the other guy.
Although the first guy had pretty good dojo decorum and dignified bearing, his behavior in the larger context was deplorable. So there's "behavior" and then there's "behavior...."