פירוש על קידושין 62:6

Fortunate is one who never saw them: As it is impossible to fulfill [the stipulations of] their honor as fully required. So he is punished over them.

His foster mother: Nanny.

R. Joseph literally thinks his mother is like God. One of my sons was like this when he was little—wanted nothing to do with me. It’s gotten better since then, but he’s still not crying out “I will arise before the Shekhinah” when I come into the room. I’m lucky if he looks up from his screen.

This is really one of the saddest portions of the Talmud I know. Honoring one’s mother and father is so difficult that it is better not to have known them.
I should say that while honoring one’s mother and father is difficult (and has been difficult for me, more than I usually admit), I certainly am happy to have shared so many years with mine, and I hope that my children someday feel the same way about me.
Abaye here claims that he never knew his mother. But elsewhere he frequently quotes his mother. The claim is that she is not his mother, but his foster-mother, the one woman who raised him.