Proposed Theory on Unhappiness
Unhappiness may just be a state of many low-grade problems, each of which can't be corrected easily.
How does this work?
Change on various scales is an important part of the happiness module in humans. We have various algorithms that seek to regulate us: we relax when stressed, eat when hungry, and work/play when bored. Being good at regulating oneself is an important skill of the happy.
So how does change occur to one's personality. From what I've been reading, people do change when they find that their personality conflicts with their expectations for life. A lazy person may find himself hurting his new family, and subsequently he would adapt through strict self-discipline. Or somebody may find their reckless alcoholism is tearing their life apart, and then they "see God" as Bush did.
But it seems like change only occurs either as a slow, evolutionary/maturation process (one that happens to you and is a function of your environment), otherwise it comes from large exogenous shocks.
But what if you want to change and don't have the benefit of large shocks, and don't want to surrender to the luck of large tectonic environmental shifts (which you usually don't have direct control over)?
Henceforth is my theory of lingering unhappiness... What if we are stuck with a bunch of low-grade problems that don't shock us and we can bear individually. For example, you could be insecure, lazy, and rude, and none of those traits are enough to make you lose your job or lose your boyfriend, but they are enough to perpetutally frustrate you. And so you try to go, "okay, new years resolution, blah blah" and you try to tackle all of them.. but without strong external pressure acting on one trait, it's hard to carry through beyond the first wave.
So unhappiness may just be like having a disease that never hurts you so much that your anti-bodies launch an offensive, but irritating enough to bring you down, one small notch at a time.
In another light, change is all about motivation. And if you are mildly motivated about many things, rather than strongly motivated about one thing, you may never have enough gusto to change any one trait in a significant way.
Usually adults give up and accept their faults. Sucks.