happiness?

Everyone deserves to be happy. I believe this to my core. Even the asshole who broke your/my heart, even the old man who has been homeless for 27 years who inadvertently gets a little spittle on your face as he asks you for change to buy a beer. Unfortunately, we are a society of one of two distinct types: those who see happiness and say, "awww" and those who see it and say, "for fucks sake". Depending on the day, I fall into either category (as do most of us?) What makes our emotions so fleeting, what makes us love and "hate" love at the same time?
Let's talk PDA, let's talk spring...It seems to me, and I may be wrong, but it seems to me that everyone is coupling. It appears everyone is affected by the new beginnings happening in nature, new beginnings occurring all over our little town. You get to a point where you start to evaluate who you are, what you believe about love, and what you want. And then, inevitably, why is it not happening for me? The bottom line, the end all be all, the most important, ME.
The more I think about it, the more I equate the whole thing to being a non-smoker in a bar full of smokers. You want it badly but you question the outcome. It's bad for me, right? It will only hurt me in the long run, right? 9 times out of 10 the feeling is short lived. 9 times out of 10 the feeling doesn't really last. And still, we crave it. We want it so badly we might just do anything to feel it coursing through our veins. Is it pessimism driving my thoughts? Or is it human nature to believe once we have been hurt, what's the point? In the end, I just chalk it up to human nature. It's all human nature. And yet I wonder, should I take it, or leave it?