I love this, Tom, and I completely agree. Chasing things that we think will make us happy is counter-intuitive and self-sabotaging; we can never find happiness in something else, for once we have it, we will only crave more. We have to find happiness in what we already have, right now.
I actually wrote an article all about happiness and how it relates to purpose. You might like it — feel free to give it a read.