Hit the nail on the head. I've quit every other social media site with the exception of HackerNews. And while some would argue HN isn't social media, I would disagree; I'd argue most of what makes HN so popular is the commenters.

I've found that in this regard, HN is no less addictive to me than a site like Reddit. I impulsively check it when I'm bored and find myself wasting time in long comment threads that over the years I have found more and more pessimistic. Still far better than Reddit, but the pessimism gets to me to a point where I can't help but feel jaded. Anyway, I just don't think it's good for me anymore.