An engineer crosses a road when a frog calls out to him, "If you kiss me, I'll turn into a beautiful princess."
He bends over, picks up the frog and puts it in his pocket. The frog speaks up again and says, "If you kiss me and turn me back into a beautiful princess, I will stay with you for one week."
The engineer takes the frog out of his pocket, smiles at it and returns it to the pocket.
The frog then cries out, "If you kiss me and turn me back, I'll do whatever you say!"
Again the engineer takes the frog out, smiles at it and puts it back into his pocket.
Finally, the frog asks, "What is the matter? I've told you I'm a beautiful princess, I'll stay with you for a month and do whatever you say. What more do you want?"
The engineer says, "Look, I'm an engineer. I don't have time for a girlfriend, but a talking frog, now that's cool!"