Existentialism also deals with the absurd but has a bit more of a hopeful attitude about it. The individual can act with authenticity and responsibility based on the level of his own consciousness, divorced from cultural conditioning, and thus find redemption in life. So it is not as totally devoid of any lightness or fun.
For example Sartre, in his Myth of Sisyphus, presents the unfortunate man who rolls a heavy stone up a mountain, only to have it fall down again when he gets to the top. So the next day, he rolls the stone up again, it falls down, over and over again until he dies. This is not a happy philosophy. Yet Sartre says that if we persist and imagine Sisyphus (ourselves) happy we will be able to get out of our state of angst and confusion. Our happiness depends on what we make of it—but it doesn't seem convincing from the example of Sisyphus.
This is why Camus, another existentialist said, “Happiness, too, is inevitable.” He was saying that in the course of life happiness and misery all happen and we can give them equal weight. Just wait around long enough and happiness will happen too. And then misery and despair will happen. Then happiness.
Angst, dread, and despair are key components of existentialism. These emotions do not fit in well with the current trends to think positively or manifest vibrationally. Angst is kind of an objectless fear. It is combined with dread to make a horrible life for the deeply thinking person who has no faith. It comes from knowing that they are out there alone, making their own decisions. So they feel vertigo, like on a high scaffold swaying in the wind.
Despair is also not an emotion a happy, positive-thinking person likes to entertain. Yet Sartre and other existentialists say that everyone is in underlying despair when they realize how quickly the rug can be taken out from under them.
Finally, Camus’ statement about suicide causes many people to hate existentialism. He says suicide makes sense as a Response to Absurdity. “There is only one really serious philosophical problem,” Camus says, “and that is suicide. Deciding whether or not life is worth living is to answer the fundamental question in philosophy. All other questions follow from that.”
Instead of seeing this statement as liberating because now they are choosing life, people see it as an argument for ending it all. Therefore, existentialism has fallen out of favor. Though it is a brilliant philosophy, people don’t look deeply into it and prefer, if they care about it at all, to look at it from a surface point of view.