Karen, The attitude shift you are expeiencing is not random or capricious. It is borne from the hard work of walking through the muck, while dropping expectation and keeping an open mind. If you stay with the process, you get to a better place. It's true we are brought here by negativity, and we do kvetch, a lot. I believe that to be a necessary step, but it's not the only step that happens here. Beyond the emotional support, we provide each other with insights, knowledge, opinion, and debate, which can serve to propel us in new directions, some which turn out to be dead ends or even wrong turns. Eventually, however, a clearer path can emerge which somehow feels right, at least for a given period of time, and that is what I wish for you, and I see you getting there.
There are plenty of reasons why people come and go here, temporarily or permanently. Participating on this board is time consuming endeavor, so once you scale a large pice of the mountain, you feel less likely to want to turn back and start again. It can be draining, too, watching others decide to come here and start their trek. And if you make it part way up, well, that's an accomplishment in and of itself, and so it is nice to take a rest and regroup. Another mountain can start looming in front of you, while the relationship mountain becomes a less urgent place to traverse. And if you've hit too many dead ends, the board, after all, may not be the best way of travel.
My personal feeling here is that if I were a better multi-tasker,and had unlimited time and motivation, I could continue to find opportunities to grow from the interactions here.