He did not say that he was wrong, he said that he cannot know for certain that he is correct.

My point is that none of us can say. Any such anecdote will be affected by biases and post-rationalisations and we even have no reason to assume we remember them correctly.

On the contrary, we have very much every reason to believe things probably happened somewhat like but still different in ways to how we remember them; I have memories of events from that age that I know for a fact can't be real. Why? Because in some of them I remember myself in the third person.

The idea that we can reliably assess how a certain action affected us is a nice fantasy, but that's also all it is. Sometimes we get it right. The problem is we can't be sure when.