"Volunteering to help others is the right thing to do, and it also boosts personal happiness; a review of research by the Corporation for National and Community Service shows that those who aid the causes they value tend to be happier and in better health. They show fewer signs of physical and mental aging. And it's not just that helpful people also tend to be healthier and happier; helping others causes happiness. "Be selfless, if only for selfish reasons," as one of my happiness paradoxes holds. About one-quarter of Americans volunteer, and of those, a third volunteer for more than a hundred hours each year."