How do you make it work? In the experience of every condo dweller I know personally, people know their neighbours mostly to the extent they bother being involved in their HOA meetings; otherwise, everyone walks their separate paths, only greeting (and maybe briefly chatting with) the neighbours as they meet them on the stairway.

It helps that it's shaped more like townhouses than an apartment building. We have a large interior carpark/garden where the kids play, which creates a lot of incidental contact and I think the kids are a huge factor in making a neighborhood feel, it creates an easy shared experience and proximity means you can easily help people out with eg shared babysitting. There's also a few people who make a dedicated effort to encourage community, like trick or treating, and it's a place where half the residents have been there over ten years. I joined the HOA in my first year which has definitely helped me get to know others.