people interacting in a overthetop friendly way, taught to smile like retards, which just comes off as annoying , invasive and extremist; but that entire culture is extremist about anything.

The US is a culture of exclamation marks and CAPITALIZED actions/reactions. And I think much of it rubbed off as the shoe of Canadian culture, even when it didn't fit the foot at all. One of these is the "conversion therapy" bill that passed through Parliament. The idea for laws criminalizing conversion therapy is mainly a consequence of the extremist religiosity in parts of the US and the also extremist reactions to it, that have been projected onto many other countries and has now been used as a template for Canadian laws.

It is ill-fitting, considering the respective timelines for the progressive milestones don't overlap particularly closely due to the relatively lack of theistic dominance in Canada. An example is how same-sex marriage passed into law 16 years ago without much opposition or hubbub. It also wasn't immediately followed by an explosion of gender ideology development until it also occurred South of the border. That's when the opportunists made their move.

In short, the culturally adjacent nations gotta stop automatically taking their cues from the US in such a reflexive manner. Some stronger sense of nationalism might help with this. Canada is pretty weak with this due to all the separatist sentiments coming from the East and the West. The physically larger the "empire", the more difficult it is to get "unity" and enforce any central mandates. This might explain why vast territories that are not blessed with resources/riches that the government can lay claim to and then bribe their overly dispersed citizens with, eventually have such overbearing central authorities, almost and oftentimes devolving into regimes in order to survive.

But anyway, there's a book I read once called, Brightsided, which talks about the smiling and positivity habit ingrained in American(and perhaps North American) culture.

I'm not much of a smiler or positive thinker(as my previous passage may indicate), so I easily took to this book as a reaction to all the people around me telling me I wasn't doing remotely enough of either. My attitude towards the former habit has always been: "I'll smile when I'm happy. It's supposed to be a emotional highlight and spontaneous. If I did it all the time it won't mean a thing anymore and the insincerity will show in my smile. And who wants that?"

On the other end of the spectrum, one of my friends normally smiles "too much", and it can get confusing sometimes if I'm not paying enough attention to their other cues to notice that they may be in a bad mood and I'm suddenly walking on egg shells. It's also problematic because I think sometimes they can inadvertently annoy other people with their habit like you said, which I tried hinting to them on occasion.

I should also note that a similar attitude exists to keep people conversing, even when one doesn't want to. You're not just allowed to be quiet and not "contribute". Because then there MUST be something wrong with you and you're gonna shoot up a school or something bad of course. It couldn't be that the person just prefers to talk with people they are familiar with and in smaller groups. And don't get me started on the emphasis on pointless small talk.