Dan Gilbert's Stumbling Upon Happiness is one of the most important books on happiness. It basically shows all the ways in which we sabotage ourselves in our quests for happiness.

He has an excellent TED talk where he rifles through some of his ideas. (thanks Stephan Stegeman!)

He says that we have terrible happiness simulators. For example, given a choice between winning the lottery and being paraplegic, we'd pick winning the lottery. The following graphic represents how most people therefore simulate their happiness about the situation:

The actual results are the following:

Lottery winners are no more happier than paraplegics. Who would've thought?

Does that mean we're stupid? No.

Does that mean we have terrible happiness simulators? Maybe.

Does that mean we shouldn't seek happiness? Absolutely not.

Here is my problem with what he's saying. What happens if you seek to make yourself a paraplegic? You will be unhappy. Here's how it would go down.

Let's say I decided right now, "okay, tomorrow, I'm going to make a plan to make myself a paraplegic." What would happen is that I would have a really restless sleep tonight. Tomorrow, when I start making the plan, my body will slow down and I'll feel incredible anxiety about my plans. As I'm about to paralyze myself, I will have incredible doubt, so much so that I probably won't have the discipline to execute on it. If I do finally execute it, then first it would be really painful. Second, the initial 2-3 months will be physically and financially grueling—not to mention emotionally—as I readjust to the world. And thirdly, even if the guilt wears off (as I'm sure people who became paraplegics because of their negligence do eventually shake the regret), I'd still be depressed because I'd have the knowledge that I'm the type of person that seeks to sabotage myself. And I wouldn't feel happy until I figured out how to make myself someone that is protective toward himself. People who treat their bodies well are the kinds of people who are happy.

THAT's my happiness simulator.

Happiness lives in the good choices you make about the future, not in the things that have happened to you in the past. Evolution wouldn't have it any other way.