There is a great video clip of Chris Rock talking about relationships. In it he says, "You can't make a woman happy. I've never met a happy woman in my life!"
This resonates with me, especially since I married a perpetually unhappy woman. But, beyond that, I think it is a fundamental truth- most women ARE unhappy. I can really only think of one woman I have known who was a genuinely happy person, at least the majority of the time. Most women, it seems, are not happy the majority of the time, although this varies with age (much less unhappiness in young women, much more in women over 30).
Why is this? I've come to a few conclusions:
Women base their happiness on the quality of their relationships with men. Men, on the other hand, base their happiness on the degree of success they have achieved in life, or on their mission.
The thing is, most women are in relationships that SUCK. The majority of men are beta males, and this results in women being unhappy with their choice of a mate. Indeed, I think that (and again, Chris Rock mentions this when he talks about women complaining about the loser they married) the majority of female unhappiness comes down to them having made poor choices.
Men, having made a poor choice, tend to either accept it and make the best of it, or else work to change it. Women do not. Their method of dealing with their poor life choices is to complain. Incessantly. And to place the blame for their choice on someone else, usually their significant other.
Other than being Alpha, and a certain amount of screening and nexting, I'm not sure how a guy can keep unhappy women out of his life. One thing I DO know is that if you don't, they will spread their misery around them like a plague carrier.