Parenting
I think that the eternal dichotomy of life is best exemplified in parenting. Juxtaposed in time are, on one hand, the joys of watching the accomplishments of your children which might in some small way reflect knowledge and behaviors that you exemplified and taught, and on the other hand, the painful realization that, as they reach maturity, they will listen to, seek out and value advice from almost any source (including unproven, uncaring sources on the internet), but will not only not seek out, but actually resent advice from the ones who may be able to provide expert advice and who care deeply about its effectiveness.
Knowing why this is so doesn’t make it any less painful for parents. And one wonders if it might explain some of the ills of our society. We hold independence in high regard which results in children loosing connection with their parents and their greater family. I hear stories about societies where a healthy balance is achieved between reaching adulthood and still valuing the experience of parents, grandparents, and the greater family. I don’t see that happening here as a rule, and I don’t consider that a societal advance.