A. if not here, where? if not now, when?
A. Nelson Mandela
A. Charles Saunders Peirce (look him up)
A. Nonexistent past the age of 7. But later, if you find work that both satisfies you and somehow contributes to the balance of the world; if you have people to love, who love you back; if you love yourself sufficiently but not too much; contentment can land, unexpectedly and briefly, like a buttefly alighting on your shoulder.
It doesn't hurt, either, if at the same time you are outside sipping a beer in the sun on the first real day of spring.