That's definitely what I felt on Reddit. It didn't matter whether your comment was relevant or not, you would get downvotes or upvotes according to your popularity and no explanation about it. I would often write comments and just press the 'Cancel' button because I felt it wasn't worth it.
I've done that so many times on Reddit, nyx. I've mostly lurked there. I found myself fearful of posting as I never knew if I'd get up voted,down voted or screamed at for existing. I dreaded getting PM's and only went to small subs where people were nice to each other. At first, I lurked a lot here and just posted content. It''s taken me a long time to get comfortable here and I find it disturbing, in hindsight, how Reddit has effected me.
I also feared that orange envelope... but I think we'll be ok here :)