People couldn't all be the same. Even fighters training in the same team had their own personalities, so the methods of support were all different. Speaking strongly worked for Angela, but for James, that would have the opposite effect.
But does that mean James listens well to the senior team members when they speak nicely? That wasn't the case either. James was a character with really strong pride. He was really proud of being from an elite wrestling background.
So unless he experienced it directly, he wouldn't follow what anyone said. Yu Jung-ak decisively beat James in wrestling. After that, James would even pretend to die at Yu Jung-ak's words. He was also quite wary of Angela. He didn't go as far as to use honorifics, but he was quite considerate of Angela's mood.
"End! 1 minute rest."