This is cause for great uncertainty because nowhere in recorded history was there any meeting of the minds that decided "let's just let everybody think that they can really achieve happiness, put this imaginary carrot on the end of a stick, and then let the entire world chase after it." Many Marxist critics of capitalism may have this view, but frankly, there's no evidence of this, and such a conspiracy would probably not go unsung, nor would it have such a lasting tenure in our present day life. It is far less ridiculous to take a structural functionalist approach to this phenomenon, in which we can see social structures evolving out of the demand to satisfy demands, and the demands to satisfy demands to satisfy demands ad infinitum. By social structures I mean anything in society that is greater than a single person. Corporations, religious organizations, political affiliations, academic institutions, and even laws - both formal and informal.
Structural Functionalism states that these structures evolve in a sort of Darwinian process in their respective environments, as if they were very complex and organic things - because they really are. Structures are things of abstraction, rather than concrete and tangible, but they are organic nonetheless because without little organic things (us) to make them up, they would fade into obscurity, and for those reasons their behaviors greatly mirror the behaviors of biologically living things.
These structures constitute the "Big Other" I was referring to. Jacques Lacan theorizes this in his developmental psychology, and the trope of the Other has been mirrored since. You might be more familiar with this concept if you were to imagine a scenario where you enter your favorite retail store and notice that "THEY REMODELED!" or "They changed the menu!" Many of you may even remember as a child asking your parents, "who is this They?" It's nobody in particular. It's a collective variable that constitutes the powers at be that are outside of your control - that dictate the social environment that you exist within and unconsciously force you to adapt to. If you live in a society of sufficient size, there will always be a Big Other.
But the big other is made up of people - people who are also very likely trying to be happy - to find something meaningful to do with their very brief lives that they can reflect upon before it's over and feel warm and fuzzy about. People who, like you, necessarily are also going to have appetites that can easily be confused with real happiness before that appetite is satisfied. This is where the structures are permitted to evolve in a way that can perpetuate this confusion on a much larger scale. Consider advertisements and marketing that seem so very certain that the thing that you really need to make yourself happier is a brand new car, or perhaps just spending a week in Vegas to have some fun - or a new fellowship to join that really knows what you need in your life to be happy.
It's also easy to buy into the error that what you really want is to "achieve happiness" because you are a being with appetites. Satisfying your appetites makes you satisfied, but it probably doesn't grant you "happiness." The Declaration of Independence famously states that all men are created equal, and are endowed by their creator with certain inalienable rights to Life, Liberty, and the Pursuit of Happiness - in fact the entire concept of liberalism rests on that very notion, but could it ever actually be attained?
Certainly there might be a few hands that may raise that would attest to the fact that they actually have achieved happiness at this point. I would like to call these hands into question. Have you really achieved happiness, or have you simply rejected the seemingly Platonic idea of happiness that I seem to be conceptualizing? Is it really the case that happiness was never such a transcendent thing at all, and what we really need is to lower our expectations - because the world isn't fair anyway? Consider Thassa, from Richard Powers's Generosity, and her blissful outlook of the world. Isn't she happy? I would very much like to ask how many would be willing to go through the gauntlet of circumstances that would bring one to Thassa's level of enlightenment. Furthermore, simply accepting that we'll never grasp a Platonic sense of happiness and settle for less is a cop-out. Settling for less is inimical to the human drive for achievement, and has measurable psychological ramifications, because satisfaction and real happiness are entirely different entities. Regardless of whether or not we are happy, we still have a responsibility to do better, because not doing so is incredibly boring.
In toto, we are chaotic things as much as we are recombinant and reflective upon ourselves. This constantly shifts our course of thought and thereby shifts the thoughts of the structures that we constitute. It forces society to evolve and revolve around the chimera of its own imagination, and it's usually pretty depressing - or at the very least mostly ironic. We don't need to ditch the idea of happiness entirely, nor do we need to "realize" it and show that "You can't have steak, just be happy with your spam instead." The alternative I offer is to recognize that the idea of happiness exists, although fleeting or unattainable - and really to stay curious, stay busy, stay chaotic, stay human, and stay unsettled.