Koreans
Based on what was shown in the documentary, among the many natural disasters and bad luck, it appeared the Korean team acted the most unprofessional. The team leader in particular was the worst, he didn't check/fix the ropes early on at base camp 4 which was his responsibility. Their team leader sat in his tent smoking while doing nothing when he was supposed to initiate the ascent. They repeatedly sat down on their descent throwing other people off their rhythm and the team leader sent 2 sherpas off to their rescue, arguing that they were paid, for which they died. Then Ger also died trying to save them.
On top of it they also seemed to have a strange attitude:
"There was a Korean guy hanging upside down," Mr Van Rooijen said. "There was a second Korean guy who held him with a rope, but he was also in shock and then a third guy was there also, and they were trying to survive. But I also had to survive."
Mr Van Rooijen said he passed them on his descent. They declined his offer of help.
http://www.telegraph.co.uk/news/worldnews/asia/pakistan/2503050/K2-cli mbers-froze-to-death-hanging-upside-down-on-ropes.html
Comfort the disturbed and disturb the comfortable