British pediatrician/psychoanalyst Donald W. Winnicott, in Home is Where We Start From:

"Your rewards come in the richness that may gradually appear in the personal potential of this or that boy or girl. And if you succeed, you must be prepared to be jealous of your children, who are getting better opportunities for personal development than you had yourselves. You will feel rewarded if one day your daughter asks you to do some babysitting for her, indicating thereby that she thinks you may be able to do this satisfactorily; or if your son wants to be like you in some way, or falls in love with a girl you would have liked yourself, had you been younger. Rewards come indirectly. And of course you know you will not be thanked."