Maybe the single best psychology lecture on the Internet is Tal Ben-Shahar’s entertaining and possibly-life changing overview of Positive Psychology: The Science of Happiness. Ben-Shahar, a psychology instructor at Harvard, talks about recent psychological research into what makes people happy. The answers won’t surprise you: it’s about relationships, meaningful work, simplicity and gratitude. Ben-Shahar also gives some easy tips on how to improve your own happiness, such as keeping a gratitude journal.
For a more detailed look at positive psychology see UC Berkeley psychology professor Dacher Keltner’ course on Human happiness.