Beckett's Endgame is very much a prime example of a dramatic movement called the Theater of the Absurd. Playwrights subscribing to this movement and its aims believed that life was fundamentally meaningless and absurd and that those characteristics should be openly displayed on stage in plays that drew attention to their artificiality and complete irrationality.

The Theater of the Absurd was closely allied to existentialism, a philosophical school that gained prominence in post-war Europe. Some existentialists, such as Jacques Maritain, were theists, but most, like Jean-Paul Sartre, were not. They saw the universe as a godless place in which people were forced to impose their own meaning on the chaotic, formless, absurd world around them.

That is precisely what Winnie does in Endgame when she says that "Nothing is funnier than unhappiness." On the face of it, this seems like an extraordinary thing to say. What on earth could possibly be funny about unhappiness?

But in her own way, what Winnie is doing here is giving us a pretty good idea of what absurdity entails. In her topsy-turvy world, a world where people have to make up their own values, she has chosen to develop a tragicomic outlook on life. It may be an absurd worldview, to be sure, believed and expressed in a world that's already absurd enough as it is, but at least it's one that Winnie has freely chosen, and for an atheist existentialist like Beckett, that's all that really matters.