I've been reading more into the book Understanding Biological Psychology. It's a fascinating book, but a little over my head from time to time. I have to work harder to understand the genetic and physiological processes of brain chemistry, but I did read a little section on addiction that was interesting and quite pertinent, I think, to what I was saying about behaviors designed to fix the bad feeling.
In the book, Philip Corr talks about the neurotransmitter receptors on the neurons that process the neurotransmitters (brain chemicals) as they enter the "dock," as it's called. In the normal state of the brain, there's an optimum number of receptors that serve to maintain "homeostasis," where the brain has a "consistent level of stimulation" (114). The brain has the ability to increase or decrease the number of receptors, depending on what the "internal processes of the brain" are telling it is needed. The ingestion of recreational drugs such as cocaine, nicotine, or amphetamine causes the brain to respond to the overstimulation by decreasing the number of receptors. That's fine until the person stops ingesting the drug, when the decreased number of receptors throws the level of stimulation out of balance; the person is in a "deficient chemical state" and suffers withdrawal. The brain takes action, increasing the number of receptors, but it takes time, so the suffering goes on for a while.
Of course, when the person goes back to ingesting the drug, the process starts all over again.
Corr mainly talks about typical drugs of abuse, including hallucinogens and alcohol. But I think that anything can become a "drug," such as gambling, shopping, hoarding, or eating. Any of these activities could effectively stimulate the brain to the point where the brain takes away the receptors, causing the deficient chemical state that then prompts the next round of drug taking.
Now, if the brain starts the process by creating the bad feeling that the person must then try to make go away by ingesting a drug or doing a particular activity, then there's no reason to assume that the brain will stop sending those erroneous signals. The mind will need to find better ways of making the feeling go away--ways that are not harmful to the person or the society.
The brain is trying to maintain homeostasis, but it's not doing a very good job, apparently. Corr talks about the "mesolimbic dopamine pathway"--"the common pathway of reinforcement and reward in the brain" (120). He says this pathway can be activated by many things, "from intellectual accomplishment to sexual orgasm." He suggests that some people have a smaller number of dopamine receptors, and that "their own internal reward system is not working too well in the first place, and this might predispose them to keep trying drugs as a means of compensating for their own naturally decreased activation of reward circuits."
It's an interesting idea, one that might explain my idea, that the brain is starting this whole thing by not working too well. And that people are rationally trying to compensate for the brain's poor performance by acting in ways that they hope will work to fix it.
So, then, achieving happiness is just a matter of making better choices about how to fix the brain's physiology.