I, too, like happiness as a goal in life. Certainly I think it's far better than constantly trying to grow the economy when we all live on a finite planet so that will have to be achieved by messing around with the figures once a certain point is reached.
In fact, my whole personal system of ethics is founded on a mix of happiness, freedom, and sustainability. The happiness is not generally short-term pleasures, though. If you partake in short-term pleasures which don't ultimately advance you in some way, you will, in the medium-to-long term, find that you feel dissatisfied and empty. The kind of happiness I think we should be aiming for is that long-term satisfaction, that deeper happiness, which comes from being on a direction in life that you find worthwhile, from achieving personal growth, or from similarly long-term pursuits.
This type of happiness sometimes needs you to put yourself through short-term discomfort or pain in order to achieve it. Imagine that somebody works out regularly, and they're in pretty good shape. The workouts themselves will be uncomfortable, but in general, the fit person will easily be able to run for a bus, to lift their backpack full of groceries/library books/whatever, to climb trees, to dance, and to move their body in general, which will increase their overall happiness. In contrast, somebody who never works out and who eats poorly and who ends up becoming morbidly obese will have had hits of short-term pleasure from the food they keep eating, but will ultimately spend most of their life in pain, from their back, their knees, their chest, and they won't be able to spontaneously climb a tree, for instance. Generally they are more likely to be unsatisfied with their life, and ultimately the short-term "tasty food" pleasure will not be enough to mask the pain. This is why I advocate being in reasonable shape for everyone who can, even though I don't see it as immoral to be out of shape, but rather non-optimal: because I want them to be happy.
(I don't really have much comment about America and its prospering or non-prospering, being English, except to say that its current effective empire is probably not sustainable, especially with the deep divides in politics over there, and therefore change will be inevitable whether Americans particularly want it or not.)