Defining happiness objectively is a dangerous thing. Utilitarians seek to maximize utility in society, and if utility is just happiness, then the goal is to maximize happiness.
Unfortunately definitions of happiness based on objective measures will fall back to physiology and will ultimately lead to definitions like the number of serotonin molecules in the brain, which is leads to disturbing corollaries.
There are many things which naturally produce serotonin - achievement of life's goals, winning Nobel prizes, maintaining large harems etc. Some people choose to take a different course and short-circuit the process by pumping drugs into their bodies. Who needs to be a god when you can just feel like one? Not the course that most of us choose, but a course which is anyone's right if they do choose it.
But an attempt to define happiness chemically is paramount to condoning slavery - provided the slave owners force their slaves to take enough happy pills to raise their serotonin levels above their pre-slavery levels.
So human happiness is not what you define it to be - it is what the individual chooses it to be for themselves. And the way to help them achieve it is by leaving them alone and letting them decide for themselves.
You have the right to the pursuit of happiness, not happiness itself. No-one will create a better society by trying to create a happier society. A better society is one which has more choice. Happiness is not society's responsibility - happiness is an individual's responsibility. If society has a responsibility, surely it is the maximization of freedom - the freedom to the pursuit of happiness.
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