Wow. I lived in Finland for a few months and this does not match my experience with them at all. In case it's relevant, my cultural background is Dutch... maybe you would say the same about us, since we also don't do the fake smiles thing? I wouldn't say that we see anyone who's polite and friendly as inferior; quite the contrary, it makes me want to work with them more rather than less. And the logical contrary for the rude example you give. But that doesn't mean that faking a cheerful mood all the time isn't disingenuous and does not inspire confidence

"I never smile if I can help it. Showing one's teeth is a submission signal in primates. When someone smiles at me, all I see is a chimpanzee begging for its life." While this famous quote from The Office may be quite exaggerated in many ways, this can nonetheless be a very real attitude in some cultures. Smiling too much can make you look goofy and foolish at best, and outright disingenuous at worst.