Happiness, I think, is all about knowing when to stop. When to stop accumulating and throw things out or store them. When to stop working and take a few months off. When to stop eating and stop drinking. When to travel, and when to stop traveling and stay in one place for a while. When to stop furnishing a house because it has everything it needs. This knowing-when-to-stop is the true meaning of post-materialism, and it's both difficult and easy to master. Difficult because we live in a society that is forever egging us on, and never wants us to stop consuming. But easy because we all have an instinct, a little voice inside, which tells us when to stop; which knows the optimum point, that particular and precious relationship between having and happiness. All we have to do is locate that voice and listen to it.