I'm not sure what it is. Either the Danish people are really friendly, I was incredibly lucky, or Americans hate strangers, but people are amazingly open in Copenhagen. You can talk to strangers, people stop on the street to help you if you look lost, and generally like hanging out and relaxing.
A coworker and I went out to a jazz bar last night. There was a table with two women sitting at a table meant for six. I just have this gut feeling that in America, we'd try to find another seat or just stand. Instead, we just went up to the girls, asked if we could join their table, and started talking. No awkwardness at all. Amazing!
The jazz bar also had an open jam session, which meant at any time, anyone could go up and sing, play a instrument or whatever you want. The two girls were music majors at a local university and decided to play some jazz. One girl was a fantastic singer with an soulfull voice that filled the room. The other has played piano for 14 years. She looked at some sheet music that she kept in her purse, memorized it in five minutes, then started jamming. Fantastic. What a great city.