RALPH: There's the rub; meaning, there's the obstacle. This comes from the game of bowls, or, as we call it in the United States, lawn bowling. You might have also heard it referred to as bocce ball — although Bocce is not actually played on a lawn, it's played on a flat dirt surface.

SARAH: The French have a version of the game called boules, or Petanque, as we call it in Provence.

RALPH: Anyway, back to the rub. So, when you rub something, you move your hand across it with pressure, creating friction. If the lawn on which you are playing this game of bowls has a slight uphill rise to it, the ball will slow down, almost as if there was some friction, or some rubbing against the lawn. So any unevenness in the lawn that slows the ball down, or changes the course of the ball, is called a rub.

RALPH: So when Hamlet says "there's the rub" , he's saying that the rub, or the obstacle, to our thinking that sleep and death are exactly the same is that we don't know what dreams are like when we're dead — this unknown aspect to death is the rub, or the obstacle, to us finding death more appealing.

SARAH: In Shakespeare's day the word was used figuratively to mean any kind of obstacle; if you hear the expression "there's the rub" today, it's because of Shakespeare. The same can be said for countless words and phrases from Shakespeare's plays.