The reason why six is the highest score awarded for media, restaurants and cultural performances is that Norway uses the teringkast or dice roll system to rate things. And (don't let any Norwegians hear this), when scores are displayed on products on a dice, see the example for Verdens verste mennesk below, the system kind of makes sense. To do this, he devised a system of displaying the film's score on dice so readers could easily see whether the movie would be worth their time.