This is another one of those things that crystallized gradually, because it kept popping up in several situations over a few days.
I think the first one was in The Art of Possibility, where she catches herself saying something like “But it wasn’t you talking. It was your jealousy.”
But the one that really clicked was the one in The E-Myth Revisited, with the story about the Skinny Guy and the Fat Guy:
One happy Sunday you decide that you gotta do something about yourself....