I personally do not justify cussing doing class as ann appropriate thing to do. I see it as a lack of respect towards the art, the teacher and the person I am working with. Sure I get frustrated for doing things wrong as well, but using bad words doesn't help do things right.
You clearly haven't heard any of my sensei's jokes, then. Respect comes in a wide variety of packages. A dojo mate from way back found himself somehow miraculously in an elevator alone with Hulk Hogan, of all people. Doug is not huge, but he was a wily midkyu at the time, and Hulk Hogan is actually ginormous. Doug didn't want to be rude and not acknowledge his good fortune of getting an elevator trip with Hulk, so he grinned, sidled up beside Mr. Hogan and said....... "WUSS." Doug says Hogan laughed, shook Doug's hand, and they had a nice talk about ukemi for a few floors. There was respect there.
I was working a concert, couple thousand people I had to pat down. A woman rolls up in a wheelchair, one of those motorized deals for folks with very little function and physical control. Guy behind her says "You gonna be a jerk and pat her down too?" Hell yeah I am. I pat her down, she's got nothing. I ask her about her backpack, guy behind her is getting bitchy at me for not giving the poor crippled girl a free pass. I search her backpack, and it's got a fat baggie full of doobs. I tell her straight up, like anyone else, " I dont care if you have a card, you CANNOT bring that shit in here. Give it up or take it back to your car." She groans but puts the chair in reverse, takes her weed back to her ride. Everyone else was shocked that poor crippled girl who was brave enough to come to a concert had a lot of grass on her, and they were more surprised that I was somehow rude enough to tell her she couldn't get in with it. She rolls back in 5 minutes later, and I search her again. She's clean, her bag is clean, her chair is clean. And she says to me, "Thank you for taking me seriously. You are the only security person in years who has had enough respect for me to actually search me." I gave her the same treatment I give anyone I pat down because she had the exact same capability as anyone to make trouble. I'm not going to look for her in a fight or crowdsurfing, but I'm sure as shit making sure she doesn't have any guns, drugs, booze, weapons, or other contraband. Respect sometimes comes out in funny ways.
Gotta go, Black Uhuru is playing tonight, and I might as well get paid to enjoy them. So much pot...........