I have a guest post from bestselling author, Gretchen Rubin on The Top 10 Lessons Learned in Happiness on Sources of Insight. Gretchen is a former lawyer from Yale, turned writer. What’s interesting to me about Gretchen is that she studied happiness by making it a project. During The Happiness Project, Gretchen spent a year test-driving every principle, tip, theory, and scientific study on happiness she could find. Her guest post is a summary of her top 10 lessons.