This is such a pertinent question and one that humanity has been trying to answer for a long time. It should go without saying that this answer will only be a scratch in the surface of such a large topic.
If we look at the Greek tradition stemming from Socrates and Plato happiness is attainable and the way to reach it is also prescribed. One of the clearest examples of this point comes from Plato's dialogue, the Symposium. Towards the end of the dialogue Socrates mentions his conversation with Diotima. In short, bliss, happiness, love, whatever you call it can be had only through dialectics.
When our minds are directed towards the divine and therefore able to cut through the shadows of this world, we can experience happiness. What this tradition states is that we need to experience the true forms or eternal realities. When this happens, there is happiness. So, happiness is certainly an experience, but it is also more. In my opinion, I think they are onto something. When we experience the perfect form of the good and beauty, we begin to experience happiness and the more we do, the happier we are.