Reddit made me extremely defensive about commenting because of the responses I got. Every time I saw my mailbox was red, I panicked. I mostly stuck to non-political subs and discussions, but even commenting on something mundane would lead to people attacking me and being rude. I started prefacing everything with, "this is just my opinion, but..." and other placating words. Really dumb when you think about it.
It was so eye opening when I had just spent months researching a topic and felt I knew what I was talking about, only to have a redditor declare I was wrong and began making false claims. When I saw how much confidence this guy had talking utter shit I realized that the comment section on Reddit is a facade of people pretending to be experts and speaking with authority despite having no knowledge on the topic at all
It's more then dumb, it's hurting discussion. Some of my views are not well accepted, trying to explain my view in a mannered way would lead to a lot of negative comments. About me, about my kind, about my mother and so on. Other times the my message will just get down voted to oblivion. But there was no discussion, my actual views got challenged very rarely. That led my to delete my account and creating a new one, one which I avoided a lot of subreddits with, nothing political. Even in the none-political subreddits I've avoided a commenting most of the time. When I did comment, the comments had to be self-censored, dumbed down. Late edit: that's not to say I think reddit is bad or irrelevant, the web-site stills works as a good content aggarator, it just mostly fails miserably when it comes to encourage well-rounded open discussion and leads to echo chambers.