I've had similar discussions about this before, although I may have been talking about religion. I think the same applies though - I would much rather live in mindful misery than blissful ignorance. I guess it's a personal choice. From your perspective, there presumably comes a point in a season at which you have to accept that your optimism is not paying off. And with that must come the disappointment of our failure to live up to your expectations. For me, I find it harder to disengage myself with reality, and this tempers my disappointment, because I never expected us to challenge in the first place. It also means that I can genuinely appreciate when we achieve something, as I know we have overcome significant odds to do it.
I would estimate that on balance, we as fans probably spend similar amounts of time being satisfied and disappointed. It's just that we have different coping mechanisms.