What's not to love

Just wondering the meaning of "what's not to love" and how, when can I use such a phrase?

This phrase is a sarcastic way of saying that something has no good features. It may have begun as a form of praise, but I always hear it used to mean the opposite. ("Big deal!" has a similar history.) "What's not to like?" seems the more common version. I believe it originated with Yiddish-speaking immigrants in the United States. ~rb