Maybe "be nice" IS all you need to be successful if you define success as giving back something of which you have an excess. Too many people define success in the standard fashion--money, houses, cars, promotions etc.
Many people in this world can benefit more from a kind word now and then as opposed to material gifts. As a parent, I can tell you my son's "Daddy, I love you" at the end of a trying day will undo all of the crap endured to that point.