Frustration requires catharsis, joy does not. Football forums fulfil an emotional function. We win, play well, I might write a couple of sentences applauding the play and get on with my day. Lose, play bad, and my day is over, I need to get that shit out of me. Negativity is no big deal, nor is tribalism in football, if you can take it with a pinch of salt. There is serious shit, like the NHS, the fucked up world/society we live in, and then there is football, important, but it's major purpose is to distract us from getting worked up about shit that really matters.