There is nothing in this universe which has the ability to completely satisfy us. Thus nobody in the world, except possibly for an enlightened being, maybe, is really satisfied in life. This general dissatisfaction is the driving force of what is called "progress": the idea that if we change this and that, then we'll be satisfied—but that is an illusion (one of the many illusions on which Western culture is based). Even if we do experience some satisfaction, it doesn't last very long. And the desire for complete satisfaction results in even greater dissatisfaction. This is called dukkha.
Closely related to this principle of chronic, universal dissatisfaction or unease is the fact that nothing in this universe is totally reliable. In other words, we can't rely on anything to keep us happy, or safe, or comfortable. But even so, we stubbornly keep searching for something on which we can rely.
We often start out with sensual pleasures, but it doesn't take a genius or an extremely sensitive person to see that sensuality doesn't deeply satisfy us, but often has the opposite effect in the long run.
By searching we eventually realize that sense pleasures are not reliable; youth and health are not reliable; money is not reliable; property is not reliable; technological progress is not reliable; social status is not reliable; friends are not reliable; romantic love is not reliable; our own parents and family are not reliable (as the Pali texts so poignantly tell us); teachers are not reliable; books are not reliable; philosophical points of view (including scientific points of view) are not reliable; good works are not reliable; formalized ethical systems are not reliable; religious faith is not reliable; renunciation is not reliable; spiritual techniques are not reliable; meditation is not reliable; even the highest attainable contemplative states are not reliable—ultimately, even we ourselves are not reliable. We cannot rely even upon our inmost selves to keep us, or anyone else, happy. We finally realize, if we are fortunate, possibly after many decades or even countless rebirths, that nothing is truly reliable. Nothing at all in this entire universe.
Upon realizing this stark fact, this inconvenient reality, we let go of the stuff to which we had been clinging, and stop trying to rely upon it: first with disgust and disillusionment perhaps, then with dispassion, and finally with penetrating insight. By not relying on anything, we become non-reliant, or in other words we become independent—we become free. This is Liberation, Nirvana. After that, we can do as we please.
But it seems first we have to do the searching, and fail, and know that we have failed. Good luck to all of you in your failing search.