What is 'Waiting for Godot' by Samuel Beckett about?

This outstanding play by Samuel Beckett is "about" the desire (some would say "need") of all humans for a purpose and direction in their lives.  For those majority of us, the "purpose" of our lives is to love, honor, and obey a "deity," a "maker" who created us for a purpose, whether that purpose is known to us or not.  Like a physical invention (philosophers have used a paper cutter as an invention whose "need" or purpose came before its creation), the prevailing view is that -- we were invented.  Existentialists, however, suggest that our existence preceded our "essence," and that we "invent" a purpose by making choices.  Returning to the play, we realize that Gogo and Didi are hoping for, wishing for, waiting for Godot, a non-character who, if he would appear, would give them purpose, orders, directions (in both senses of the word.)  The play, then, follows the two universal characters through their daily lives while they wait, performing basically meaningless acts to "pass the time".  The impact of the play's message is made frighteningly clear when at the end of the play, this exchange -- "Let's go."  "Yes, let's go." -- is followed by the stage direction:  "They do not move."  In every good production, the audience is frozen in place for several minutes, because we, too, are "waiting for Godot," for purpose and meaning.