1. A declaration of complete approval, usually said after listing several qualities of the thing being approved; frequently used in an ironic or sarcastic sense. Popularized by sitcoms like Friends
2. Title of a Hannah Montana
"He's tall, he's sweet, has a great sense of humor, and he has a great job - what's not to like?"
"Upset? Why would I be upset? We've totaled the car, we can't get out, we wrecked an orphanage, the cops are on the way, and we've got 3 kilos in the trunk! I mean, what's not to like?"
Ross: It tastes like feet!
Joey Tribbiani: Well, I like it.
Ross: Are you kidding?
Joey Tribbiani: I mean, what's not to like? Custard, good. Jam, good. Meat, good!