An economics graduate student was crossing the road one day when a frog called out to him and said, “if you kiss me, I’ll turn into a beautiful princess.” The student picks up the frog and puts it in his pocket.
The frog spoke up again and said, “if you kiss me and turn me back into a beautiful princess. I’ll stay with you for one week.” The student takes the frog out of his pocket, smiles at it, and puts it back into his pocket.
Desperate, the frog then cries out, “What is the matter? I told you that I’m a beautiful princess, that I’ll be your girlfriend and do anything you want. Why won’t you kiss me?” The grad student said, “Look, I’m an economist. I have no idea what it would be like to have a girlfriend. But a talking frog would be worth a Fortune.”