I feel like I need to state my "credentials" before posting my opinion on this movie. I am a non-Norwegian who's been married to a Norwegian for 10 years so have literally been the "outsider" at a Norwegian family Christmas in a similar way to the Jashan character in the film when we first got together. Since then I have lived in Norway for a time and become very familiar with the culture, language etc. As such, I thought the film was overall pretty enjoyable and found that the situation portrayed in the film was very accurate and relatable, albeit in an exaggerated, comedic way.
I am surprised at the low ratings this film has received and I feel like a lot of the negative reviews of the film are taking it FAR too seriously and people are being extremely sensitive about the issues portrayed. Yes, the "Norwegian-ness" of the Norwegian characters in the film is somewhat cliche and their insularity is exaggerated. However, it's a light-hearted Xmas comedy! It's not supposed to be a documentary, or be a serious look at cultural and social issues around race and identity.
I actually felt that the film did quite a good job at making all sides partially to blame for the misunderstandings that arise, which is generally the case in situations where no side is being deliberately malicious. The overall moral of the story seems to be that sensitivity, patience and understanding are the solution for the differences that naturally arise when different people and cultures meet.
All in all, I think people need to chill out and adjust their expectations regarding this film.