I read the title expecting to agree with you, because negativity bothers me, and I agree that there is a lot of it around.
But I have to say that I am much more bothered by general negativity ("children have no manners anymore" "this country is not like it used to be", "you have to have a gun" etc) rather than the "OMG I am so PI%%ED about this one thing that happened me today!" posts, which I see mostly just as outbursts, rather than chronic negativity.
I am sorry that you are experiencing these posts in that way and that it is ruining your experience of this board, which I think is a really great resource.