It carries over to their other interactions - I generally found Koreans to be more extroverted, social, less meek, more firm, making decisions faster, and less bureaucratic than average.
There could be other factors contributing to this, though - there's mandatory military service, so a lot of the men there carry themselves like soldiers. Overall though, I was quite impressed with Koreans and Korea in general. I was lost at one point near Seoul Station, asked a police officer, and he walked me 10 minutes to where I was going while having a chat about the USA, South Korea, politics, and other things - very strong, but also very social and a good guy. I felt some hostility at certain times at Seoul, but I also haven't felt so welcome in a place since I was in Italy. Funny how that all works out.