I think that there are lots of possible reasons for this. Also very big, as Ozzie pointed out, that sometimes people say the opposite, which could be a different swing of the pendulum OR could be a different perception of the same situation.

I can tell you about my posting habits which may shed light on two possible explanations of the many that may exist.

First of all, I do try to post positive, supportive posts to good news. But also right now, I have a lot of very bad triggers and I am in a very bad place. My car being repossesed and my difficulty getting around is a huge trigger right now. And sometimes I find myself starting to post a positive message to a positive post and realize that it is becoming a negative post about how bad I feel. I try to keep these things out of positive threads and instead put them in my personal threads.

So that is why right now it is easy for me to post about someone's new job but difficult for me to post about someone's new car. I am always very happy about the good news (I do not have a tendency to get stuck in a "why me?" mode, luckily) but when I try to express that, the depression takes control of my fingers on my keyboard, so I back off.

The second thing is that I post (this goes for all posts) to things I can relate to. As you can imagine, just from sheer statistical mathematics there are a lot of threads I can "relate to" in the depression forum, but only a smaller percentage of things I can relate to out of the number of "good things" threads. I can relate to a new job, a new car, a new cat... but I can't relate to a new horse, or a new baby, or a wedding, or a trip somewhere. Which doesn't mean I can't or don't respond to these threads... just that I don't seek them out as enthusiastically. Those were probably bad examples, because a new baby or wedding is something worthy of a "Congratulations!" in any case. But there are other things not as large on the scale, things that are worth being happy and excited about, but that just don't grab my attention, if you know what I mean.

My posting style is also that I generally post when I have something to contribute. I almost always post a message, the only times I post nothing but a hug are when I feel that it is a significant contribution from someone who knows me or someone that says something I really empathize with. That is just me... I really appreciate long threads here with lots of simple replies... I think it is supportive and necessary in a community like this... it is simply not my personal style. Sometimes I wish otherwise but mostly I am happy with the way I am.

We do have to be aware of "perception" here. Many may think I am not friendly or that I am "cliquish" because I don't spread hugs more. I don't believe that is the case with me, I try to respond to everything I can relate to no matter who it is from. (I also enter threads based on subject line... I don't look at who posted the thread, just the topic). And people have different needs. So some people will do good with a long chain of replies and others simply need to post to get it "out there". At times when I am depressed and isolated like I am now, I have to say that for me, I do like the replies

So I guess I'm saying my replies are a combination of "what the person needs (in my view)" and "what I have to offer". We have such a large and varied membership here that if everyone does that, hopefully it will work out with most people getting their needs met. And others telling people when their needs are not met, and what their expectations are, which I always think is a great thing for the growth of this community AND for the growth of the person asking.