HN still suffers from what I call the "Everyone is an idiot but me" mentality. There is also a bit of outrage from time to time about small things. But the fact that it is the worst that happens here is saying a lot though. HN really is very well moderated and the guidelines are concise, reasonable, and simple to understand. It really helps that HN has a narrow set of topics. No idea how this could possibly scale to the size of twitter.