(A foreigner living in Norway here.) You can relatively often hear Norwegians joking about Swedes, and vice-versa. So I asked a friend of mine (he's Norwegian) about this "friendly hostility", to which he replied: "Norway has oil, Sweden has industry."
Another, probably little-known fact, [I can't dig out a historical reference -- I remember conversations with people] is that Norway offered Sweden to jointly engage in oil extraction in the early days, which Sweden declined.
Another, probably little-known fact, [I can't dig out a historical reference -- I remember conversations with people] is that Norway offered Sweden to jointly engage in oil extraction in the early days, which Sweden declined.