This is nothing new but interesting, I hope. I've recently been reading different sorts of parables. I'm struck by the economics and policy implications in many of them.

Some of my favorites:
-Absence makes the heart grow fonder (diminishing marginal utility).
-A bird in the hand is worth two in the bush (depends on your discount rate).
-Don't cry over spilt milk (sunk costs).
-Don't put all your eggs in one basket (diversify your portfolio).
-Don't throw out the baby with the bathwater (heterodox schools of thought).
-Don't lock the stable door once the horse is gone (sometimes it's better not to rebuild).
-The game isn't worth the candle (information costs).
-Good fences make good neighbors (property rights).
-Life is short; art is long (structure of production).
-There's no accounting for tastes.
-Too many cooks spoils the broth (diminishing marginal product).
-You can't have yoru cake and eat it too (opportunity cost).
-You can't make an omelet without breaking eggs (creative destruction).

Tyler Cowen's favorite Haitian proverbs offer similar implications.

Menken speaks to Art's post below about systematic voter beliefs.
"Noone ever went broke underestimating the intelligence of the American people." (Of course, we know it's the low costs of being wrong, not intelligence, at issue.)

A good Chinese proverb for the classroom:
-He who asks is a fool for five minutes, but he who does not ask is a fool forever.

A couple of Mexican proverbs I managed to retain,
-Hay mas tiempo que la vida (there is more time than life).
-Salud, amor, dinero, y tiempo para gustarlo (health, love, money, and time to enjoy)

The Bartleby Dictionary of Cultural Literacy has a nice introduction in its entry on Proverbs:

Well, back to work. As they say, it's best to make hay while the sun shines.

Do you have some favorites, comments open.