In the context to this blog entry happiness is made up of two-parts - pleasure and purpose. There is pleasure (or pain) and purpose (or pointlessness) in all that you do and feel. They are separate components that make up your overall happiness that comes from what you experience. You are happiest when you manage to strike a balance between pleasure and purpose that works best for you.
Attention is the Glue
Unfortunately, it is not uncommon for us to pay more attention to what we think should make us happy rather than focusing on what actually does. Too often we evaluate something as satisfactory even when the actual experience is not pleasurable, leading to poor choices about what really gives us happiness.