I'm currently 7th kyu in Shitoryu Karate, got a long way to go before coming close to any black belt in my dojo but I still love the thrill of kumite.
So anyways there was one time where this punkish looking guy joined the dojo, and he had this really obnoxious look. Excused himself during the idoshiki, came to class only after we greeted the senseis, and I caught him picking on the younger students a few times. He's prolly one of those guys who's always looking for a fight and thinks they're tough [censored], which is common in my country.
I finally got a chance to spar with him during one of the free sparring sessions, used some of the advanced footwork techniques they taught during the kumite division class to sidestep his punches, then when he tried a mawashi (which didn't look like one by the way), I bypassed it and landed a triple reverse punch right smack on his solar plexus.