These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Sister Japan. Before being introduced, the fan club had a large number of submissions speculating what she'd look like, Humon introduced her just to get it out of the way, and a popular character was born.
After Coat Of Arms came out, the other lions were quickly forgotten, but Special Lion became a fan favorite and has stuck around. There's even offical merch with him on it!
Hollywood Homely: Averted, Humon goes out of her way to show how Finland and his sister are not sexy beautiful people, and are plain at best. She also tries to show that Norway is also just slightly overweight, and has recently adjusted Sister Denmark's character design to make it clearer that she's meant to look more masculine.
Les Yay: Sister Norway and Sister Denmark. Sister Sweden and... well, everyone.
Mexicans Love Speedy Gonzales: Pretty much any fan of the comic, since all the characters are based on national stereotypes. As far as non-nation characters go, Special Lion is this for the Finnish. Most Finns think the whole "retarded lion" joke is Actually Pretty Funny, to the point that one posted "go go retarded lion!" after Finland won the World Hockey Championships.