I've understood for a few years now that I am the one in control of my happiness, and that greed and wanting more than you can realistically get is a sure way to avoid happiness. The thing that I adored most about my college psychology classes (I got a psych minor!) was hearing about experiments that gave counterintuitive, unexpected results, like the famous Milgram experiment, which, in attempting to explain how the Holocaust could have happened, showed that ordinary people are capable of being incredibly cruel to others if they are ordered to do so by an authority figure. Another example that I recall is the Stanford prison experiment, where ordinary college student subjects were randomly chosen to be prisoners and guards in an experiment. Within a few days, both groups started showing the exact emotions and abusive behaviors that are seen in real prisons.
Anyway, if you care at all about being happy and want to know how to be happy, you MUST watch this video! It's 20 minutes long, but it could change your life.
Dan Gilbert, the speaker, is great lecturer. I would love to go to some of his psych classes. Unfortunately, I'm not a student at Harvard. He's written a book called Stumbling on Happiness, in case your interested further.
By the way, he mentions Ze Frank because Ze also gave a talk at the TED conference. Worth watching for Ze fans and non-Ze fans alike.