Adam Smith teaches that individuals behaving egoistically also benefit everybody else. Now we have to realise that individuals being benevolent towards others (everybody except the most ungrateful) will first and foremost benefit themselves! Directly by the satisfaction that blesses the benefactors. And indirectly when some of their actions some day lead to more benevolent behaviour of others.(*)
Smith's law might still be a valid principle of economics, but it's inverse is a principle of human nature that's ever-more important in our era-of-plenty. The social matters more than the economic! (Remember, Obama's campaign was won with grass-roots participation, not with high-valued donations.)
(*) I write "some of their actions lead to an indirect pay-off sometimes" because if there was a guaranteed result, the action would not be benevolent, but just an egoistic calculation. Feedback of benevolence works only on average and in the long term (and it's rewards are positive surprises as opposed to the expected outcomes from calculated action). But the direct satisfaction of doing something good always works.