In my experience there's no place like HN on the internet, and that's due I suspect to having a highly professional moderator (@dang) who uses top level communication skills to firmly but politely pull people into line.
That in turn creates a virtuous circle where users socially moderate each other.
It's hard to describe just how relaxing and pleasant it is browsing HN. It's always jarring to read the comments on e.g some Facebook groups I belong to, which feel like they're authored by a bunch of teenagers that have just found the key to their parents liquor cabinet.
If Twitter was like HN I would spend time there.