The psychological immune system is coinage for the idea that although we think that our goal in life is happiness, our brains are wired not to seek happiness, but to seek normality.

That is fascinating to me. I've always thought that I was living my life for some lofty goal of happiness, but it seems as though our brains are wired to feel unaffected. This explains why we often get over things quicker than we thought we would (when we let ourselves) or why the things we indulge in aren't ultimately as fulfilling as we thought they'd be.

Happiness, whether you're able to think of it like this or not, is really just a result of chemicals in our brain. You may think that your goal is a good job, a healthy relationship, and a nice steak dinner--but your goals are ultimately serotonin, dopamine and norepinephrine.