The subject I've researched the most and written about the least is the happiness. Instead of putting off the version of this that reads like a research paper with sources cited and so on, I will just tell you a rambling story. And for full disclosure, my own level of happiness from 1 to 10 is about a 7. I am currently below the US's average answer of 7.4. (Note that Switzerland, Iceland, and Denmark are all above 8.0 averages).

A Crash Course in Happiness

For 100 years, the field of psychology was concerned with fixing problems in people, and the study of "happiness" was considered not a topic worthy of study. You couldn't even say the word happiness in an academic paper, you instead needed a jargony term: "positive affect." In more recent times, we now know that happiness is NOT the absence of misery. The absence of misery is being kind of neutral at best. People who have misery can simultaneously be very happy, even (more on that in a bit). The point is, even though last century's psychology was highly successful at curing various mental ailments, we now know that actual happiness requires more than that.

Happiness is in many ways a trap. It's evolutionary biology's way of making sure we keep going, and keep seeking. That is why happiness is so elusive; by its very design in our brains, it's something out there beyond our reach, something to strive for. Those of our ancient ancestors that were completely satisfied with what they had were less likely to go over that next hill in search of the greener grass and more resources, and thus less likely to win the competition of survival of the fittest.

Money is a big trap for many. One of the most consistent findings in this field is that money has zero correlation to happiness, except for the poorest people in the world. If getting more money will help you meet your basic biological needs for food, water, and shelter, then yes it will make you more happy. Beyond that, it won't, but it damned sure seems like it would, doesn't it? There's a corollary here that is especially relevant to American culture. Americans tend to work more hours than workers in other countries. Let's say you make enough money that you live comfortably. You get an opportunity for a promotion at work which means more responsibility, more hours, and more money. We are conditioned to believe this is a no-brainer of a choice: of course you take the promotion because more money is more happiness. But it isn't. If the job would be more personally fulfilling to you APART from the money, it could increase your happiness. But if it's not, then you're trading away more of your personal time in exchange for money that won't make you happier. You'd actually be happier if you worked LESS, rather than more, if it's a job that you aren't passionate about. 

More money lets you buy more material goods. A new TV would be nice. And a new clothes. And a new car, and so on. When you get that awesome new TV, the awesomeness of it wears off after a short time. You are going to be very bad at predicting that ahead of time (we all are). You're bad at predicting how much happier the TV will make you and for how long, at how a political election will affect your happiness, at how the death of a family member will affect you, your favorite sports team losing, winning the lottery, and just about anything else. In all these cases, the feeling you predict may very well become real, but it lasts a much shorter time than you would expect. The TV becomes just another thing very quickly. You bounce back from the death of a loved one, even if takes a month or a year, but when it happens the sadness seems like it will be permanent. One study compares the happiness levels of people who won the lottery with people who became paraplegics (can't use their legs) because of an accident. Although right after these events, the happiness levels are what you would expect, after one or two years they level out to be exactly the same across both groups. Yes, really.

The term "hedonic treadmill" is