A farmer owned a Goose that laid one golden egg every day. Growing greedy and impatient, he decided the Goose must be full of gold inside, and he killed it to take it all at once. But inside it was just like any other goose, and now there were no more golden eggs at all.

Moral: Greed for more often destroys the good you already have.

From Aesop's Fables, public domain.