One more thing to say on the subject.
Today I read this talk by Bruce Hafen, given in the late 1970's at BYU. I'm so glad I stumbled across it. It was just what I needed to hear.
In the talk, he quotes an English writer who laments the uselessness of both pessimists and optimists. Yet, he doesn't say that the third group are the standard "realists." He calls them the improvers. In other words, these are the people that see both the good and the bad--unwilling to either whitewash what they can't deal with or dwell on all that is wrong and relish being critical--but they choose to make the most of the world as it is. Improvers aren't naive, nor are they cynical, Hafen explains that they are those who have moved past each of these places into a category where they might actually do some good in the world.
It will take some time to go through the talk. It isn't short. But it is so wonderfully illuminating.