Maybe I put it a bit wrong in my previous post about that girl. She was former karate student (black belt) and she was the one that was a bit arrogant; Every time when someone tried to explain her some technique she was always reacting in a "leave me alone I already know this" manner... and at the end every class she would intentionally get in a way and disturb us while we were folding our hakamas (for example she would intentionally step on it or pull those cords used to tie hakama and disturb our work), and when we asked her not to do it she wouldn't listen, or even threaten us with her karate skill.