Re your edit: Yeah based on all the replies so far I think I must've given the wrong impression in my original post. Too much emotion, makes it hard to interpret reality.
I think this maybe gets to the core of the problem, that it's not really to do with the social setting per se, but my attachment with it, and the expectations that go along with it.
Just like here on HN, I easily get carried away with idealizing the place and then become overbearing, too eager to impress. Same online or offline. Except maybe offline, what I've realized, is that people easily get overwhelmed by my eagerness, so they kinda just step back from it all, not wanting to get involved. Whereas online, I can't really overwhelm anyone cuz it's all thrown into the air, and anyone who cares will respond, and those who don't just move on. That's my theory anyway.
But in general, I think the context around us really does matter a lot, like you mentioned. Not just the types of people we meet, but the expectations we/I set up with it.
Another thought that I'm starting to explore, is that perhaps I'm the one that isn't smart enough or well-read enough to carry a conversation with anyone about anything. Whereas online/HN I can pick the topics I know about and go contribute there.
Lots to think about. Me + social life = confusion to the max. And I've been thinking about it and trying things out a lot, and still can't figure it out.