What everyone wants from life is continuous and genuine happiness," said 17th century philosopher Baruch Spinoza. I believe this is true. While it is possible to imagine people who wish to be unhappy, you would rightly think there was something wrong with them. They can't be rational; they must have a mistaken idea about what life is about, or they may be suffering from a psychological disorder. It is irrational to desire unhappiness.
Long before Spinoza, ever since the tradition of Classical Greek philosophy declared that human flourishing (happiness) is the goal of life, people have been trying to figure out what happiness is and the best ways to achieve it. But if the ancient philosophers were to look at the world today, they might well conclude that we aren't the rational creatures they had in mind, for what we now designate as happiness is an idea that they rejected.
The modern concept of happiness rests upon the philosophical and psychological theories of the supremacy of the individual. I believe that the self-centeredness and individualism that follow from these theories undermine the possibility of achieving happiness at all.