I don't think there is a factual answer to this. It is all opinion and interpretation.
I'm a liberal leaning libertarian. ALL of my neighbors are lower income conservatives. We are the only home on the block without constant drama. The only house that doesn't have an ambulance pulling up a couple times a week to it.
Yet the majority of my associates are either anarchist, libertarians, or liberals and they all seem pretty happy with their lives. They all have good jobs. Some are veterans, some are stay at home homeschooling mamas, while some are the average working middle class. My associates are usually up beat people who attend local fund raisers, get togethers, and often set up outings for our group.
However, if I had to make an educated guess, I'd say conservatives as a whole are probably happier here in the USA for one reason only. Low income people are more apt to be less happy and considering the amount of poverty among minorities (which are not always, but usually liberal) I would assume there is more unhappiness among them. Yet my neighbors are mostly miserable poor white people and they are all conservative.
So again, it's all opinion, interpretation, and speculation.