CS Gang,
I like this altered saying:

"You can lead a horse to water, but you can't make
him think.!! "             

   or...........

How about :           "casting pearls before swine"
I mentioned that one to my wife and got into
boucoup trouble, but it still fits.

After 30 years of trying. I only mention helpful,
working, alternatives once, then feel I've done all
I can do. If the person is ready, the questions
will come. If not, I tried.

Tom Bassett