Sartre's play, The Flies, dramatizes the Greek legend of Orestes, a man who murders his mother and her husband. Normally, a person in Orestes' situation would quake as he awaited divine punishment, but not Orestes. He rises above such fear, shouting at Jupiter: “I am neither master nor slave. I am my own freedom! Hardly hadst though created me when I already ceased to be thy own!” Orestes realizes that he merely exists, with no laws implanted in or overseeing him. He can accordingly do whatever he wants. Intense freedom is his. Any reminders of the moral laws that he might experience, those pricks of conscience, are nothing more than annoying flies. Swat the flies, Sartre says, and man regains his total freedom.
Now, I reject Sartre's existentialism. It is logically inconsistent because it tells us to reject all criteria in the name of choosing one's own criteria. It also rejects all goodness and virtue. But there's something there. Something true and good. The importance of existing, first and foremost, is a good premise. This theme starts to emerge, in a good way, in the work of Camus, Sartre's one-time disciple.