Waiting for Godot is a play about waiting. Discuss.

The two tramps in Waiting for Godot, Vladimir and Estragon, are seen awaiting the arrival of Godot for the entire play. In both act 1 and act 2, a boy messenger arrives to inform them that Godot will not appear that day, "but surely tomorrow." Since Beckett plays with time and memory in the play, we are not sure how long they have been waiting. They are both "unreliable narrators" of events both in the recent and not-so-recent past, but it's apparent this is not their fault.
Godot, the character for whom they wait, is one of the most discussed offstage characters of modern literature. The simple—and to a degree, cliched—explanation, is that Godot represents God, therefore portraying that simpleminded humans continue to wait for someone to come (in the case of the Christian concept of Jesus) and that since that someone does not exist, they'll be waiting forever.
But Beckett created a much more subtle and radical play than that. Does it really matter for whom they wait? What or who are we all waiting for? Death? Why is Pozzo waiting to sell Lucky? Isn't it in fact true that the only meaning in an "absurd" and unknowable universe is to be found in the simple relationships that exist here and now?
By the end of the play, the audience has accepted that waiting is all that Vladimir and Estragon will ever know, and yet they go on. They do not hang themselves; they simply go on.