I agree on the polite, but I also find that we're (I don't claim to be superior) more closed than other maybe more brusque residents of places like New York. Striking up conversations with random Vancouverites can be hard to do, though pleasantries are easy if that's your thing. Service is also the friendliest of any city I've been to, though not as friendly as in small towns and often of the cloying and fake variety. Still, it's nice after you've been buffeted around in Berlin cafes for a while.
I'm here now after living on the East Coast, Toronto, and Saskatchewan. I've spent a lot of time in Montreal, Seattle and San Francisco/Bay Area, and I've been to most of the major cities in the US except NYC (well technically I have but too young) and the southern states.
What you say is totally true. The social dynamic in Vancouver is very superficial. People are 'nice' but there is often no substance to your interactions with them. Groups of friends are very clique-y and closed. The dating scene here is just ... weird. I guarantee you it is easier to 200% easier to date anywhere else in the country, and this has been repeatedly corroborated by co-workers who have moved here from Europe and Toronto/Montreal.
I heard it said that it easier to get laid in Vancouver than date (unless it is incestuously within your closed social circle), and I think that's extremely accurate. That to me symbolizes the whole situation here. It is easier to get a meaningless interaction like casual sex than it is to develop something meaningful.
In terms of art and culture, this city is surprisingly dead. Several stage actors tell me it is easier to make a living in Calgary. The art gallery scene is similarly clique-y and generally expensive. The indie music scene isn't superior to the rest of Canada.
Partying is horrid, which isn't that much of an issue for me as I've been trying to live a much cleaner life since getting here. But if I was still in my party days I would much rather be in Toronto or Montreal - it's more concentrated and less inhibited.
The job market ... yeah, not so good as a whole. Of course some sectors are strong here like anywhere but it just doesn't have the overall earning potential, plus everything is so expensive.
Fun, random things are difficult here. It's nigh impossible to go somewhere cool at 5AM like I used to. Hell, I would settle for being able to eat somewhere decent at that time. You can't get super messed up and stay out because there aren't that many cheap modes of transportation - skytrain is closed ridiculously early and cabs are exorbitantly expensive.
Having said that, this place is breathtakingly beautiful. I've been here for 8 years and at least every other day I have a "I can't believe I live here" moment. The women are gorgeous. The weed is amazing. I don't have to shovel in the winter. I don't feel like I am lining my lungs with soot when I breathe. The water comes out of the tap clean. Golf is accessible (if not as numerous) and relatively cheap. Ditto for snow and water sports although I am not as into them. There are a decent amount of rinks for hockey and of course Vancouver can't be beat for just getting out into nature and hiking. Sushi ... seriously, seafood could be the sole reason to live here. In general there is a lot of good ethnic food. Beaches are stupidly convenient.
In short, I love it here. Haters gonna hate.
