What's your interpretation of the saying "Therein lies the rough"?

Question

Heard it for the first time today and stumped.

Answer 1

You mean: "Therein lies the RUB"...

"That's the problem"

Sorta' like "The only thing is..." AFTER the problem instead

of BEFORE it.

Answer 2

I think the quote is supposed to be "therein lies the rub", which is derived from Shakespeare's HAMLET, where Hamlet says "there's the rub" to mean, basically, there's the problem or dilemma.  Here's the quote:

To die, to sleep--

To sleep--perchance to dream: ay, there's the rub,

For in that sleep of death what dreams may come

When we have shuffled off this mortal coil,

Must give us pause.