Norway also has a weekly tradition called "Taco Friday" that a decent amount of people participate in, so it's safe to say that generalizing food habits doesn't really work anymore nowadays.
I grew up in Norway. The way I see it is that weekends are for spoiling yourself with the most delicious food. Another common tradition would be making pizza on weekends. Taco Friday is seen as a special weekend treat.
I know taco and pizza aren't really that special or fancy meals, but I guess they turned out that way in Norway since they came from abroad. They're still not seen as "fancy", but they are many people's favorite tastiest food.
(I ask with all seriousness; I'm kind of hoping the answer is interesting)