I think this is a wonderful topic, but I have reservations about exactly how one maintains a positive attitutde through the vicitudes of life. Even the most Pollyanna-ish person has to have a breaking point - unless they're delusional.
There is an old stand-up comedy routine I remember from the old days in NYC, where the comedian is talking about his Catholic school experiences. When the nun tells the class that if they sin they will suffer in Hell for eternity and he asks her how long eternity is, she replies:
"If a little sparrow comes once a year to sharpen his beak on the sie of a 10,000-foot granite mountain, the time it takes for that mountain to wear down to a grain of sand small enough to fit through the eye of a needle ...
... that's ONE SECOND in eternity!"
... at which point even the Honor students are jumping out windows, etc., etc.
Similarly, living a long, full life must lead to at least a few bad experiences. Yes, you can "get over them" but I think the longer you live the more such experiences you're likely to have, and the more that mountain of positivity is going to be worn away.
For me, reality is the judgement I use - reality based upon experience. I've seen cancer patients as mentioned that were wonderfully positive - but I've also seen them writhing in pain from their treatments. Just the knowledge that there ARE people experiencing pain like that moderates my positive attitude. I don't trust the medical profession when they tell me fairy stories, and I've seen that the pain is very real, so how do you keep a positive attitude when you're going through all that?
I had two aunts that lived to their late 90's, the last 3 or so spent in nursing homes. They were like Yin and Yang - one was a realist that rarely smiled, wasn't much of a church-goer and was always business-like; the other was trusting of people (to a fault) and trusted her God to always provide and protect.
Two totally different personalities and ways of looking at the world, yet they both cried from their pain toward the end.
As a realist, I cannot in all good faith believe that everything turns out great when I know that in reality it does not. I don't linger on the negative, at least I try not to, but neither do I skip around with unicorns throwing out Skittles. I try to be balanced, which means not being totally negative but also not being totally positive.
