I read it more softly than that. Of course we get 'paid back' for making the Thanksgiving turkey - by goodwill. I'm paid for moral acts by a reinforced self-image and satisfaction. There are lots of forms of payment.
Right, but those feelings are the result of the culture you were raised in and the normal feelings of compassion you have as a member of a highly social species of animal. The whole reason society works at all is because I teach my kids to share, and not to hurt each other. If everyone starts believing that they should only do things out of pure self interest, then I'd say you're looking at a society that's about to degenerate into warfare, slavery, and violence.
